Hyaluronan as a drug pre-sensitizer and chemo-sensitizer in the treatment of disease

ABSTRACT

This application provides methods and compositions for the treatment of cancer. The application provides compositions comprising hyaluronic acid and a chemotherapeutic agent such as irinotecan that are useful in the treatment of cancer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 10/088,774, filed on Mar. 13, 2003, which is a National PhaseApplication under 35 U.S.C. §371 of International Application No.PCT/AU01/00849 filed Jul. 13, 2001 and claims the benefit of AustralianApplication No. PQ 8795 filed Jul. 14, 2000, the entire contents ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the enhancement of bioavailability ofchemotherapeutic agents for the treatment of disease. In particular, thepresent invention relates to the use of hyaluronan either alone or incombination with a chemotherapeutic agent, e.g., irinotecan orderivatives thereof, to enhance the bioavailability of thechemotherapeutic agent for treatment of disease. The present inventionalso relates to the treatment of a drug resistant disease whereby thedrug resistance is overcome or alleviated with the use of hyaluronaneither alone or in combination with a chemotherapeutic agent, orderivatives thereof.

BACKGROUND TO THE INVENTION

Many diseases that afflict animals, including humans, are treated withchemotherapeutic agents. For example, chemotherapeutic agents haveproven valuable in the treatment of neoplastic disorders includingconnective or autoimmune diseases, metabolic disorders, anddermatological diseases, and many of these agents are highly effectiveand do not suffer from any bioavailability problems.

Proper use of chemotherapeutic agents requires a thorough familiaritywith the natural history and pathophysiology of the disease beforeselecting the chemotherapeutic agent, determining a dose, andundertaking therapy. Each subject must be carefully evaluated, withattention directed toward factors which may potentiate toxicity, such asovert or occult infections, bleeding dyscrasias, poor nutritionalstatus, and severe metabolic disturbances. In addition, the functionalcondition of certain major organs, such as liver, kidneys, and bonemarrow, is extremely important. Therefore, the selection of theappropriate chemotherapeutic agent and devising an effective therapeuticregimen is influenced by the presentation of the subject. Suchconsiderations affect the dosage and type of drug administered.

Unfortunately, not all chemotherapeutics are readily useable. Forexample, some chemotherapeutic agents are inherently refractory in thatanimal cells do not readily respond to these agents, while otherchemotherapeutics suffer from acquired resistance. For instance, it iswell recognized that some subjects on prolonged chemotherapy are forcedto change chemotherapeutics as these become less efficacious with time.Moreover, some chemotherapeutics, while not affected by inherent oracquired resistance per se, are not effective in the treatment ofcertain diseases as they have innate problems with bioavailability. Onedisease that is frequently affected by both cellular resistance andbioavailability problems is cancer.

Cancer is responsible for one in four deaths in Western society. Whilethe rates of new cases of cancer and deaths with cancer decreased in theUnited States and Canada between 1990-1994, the data show that 2,604,650people in the United States died from cancer between 1990-1994, withmore men (53%) than women (47%) affected. The most common cancer deathswere due to cancer of the lung (728,641), colon and rectum (285,724),breast (218,786), and prostate (169,943).

Among women, the most common cancers are breast (31%), lung (12%), colonand rectum (12%), uterus {6%), and ovary (4%), with breast and ovariancancer representing approximately 35% of all cancers found in women. Themajority of women diagnosed with these forms of cancer receive acombination of surgical, radiation therapy or chemotherapy.

Chemotherapeutic agents used to treat cancer can be subdivided intoseveral broad categories, including, (1) alkylating agents, such asmechlorethamine, cyclophosphamide, melphalan, uracil mustard,chlorambucil, busulfan, carmustine, lomustine, semustine,streptozoticin, and decrabazine; (2) antimetabolites, such asmethotrexate, fluorouracil, fluorodeoxyuridine, cytarabine, azarabine,idoxuridine, mercaptopurine, azathioprine, thioguanine, and adeninearabinoside; (3) natural product derivatives, such as irinotecanhydrochloride, vinblastine, vincristine, dactinomycin, daunorubicin,doxorubicin, mithramycin, taxanes (e.g., paclitaxel) bleomycin,etoposide, teniposide, and mitomycin C; and (4) miscellaneous agents,such as hydroxyurea, procarbezine, mititane, and cisplatinum.

Particular chemotherapeutic compounds used in the methods andcompositions of the invention include topoisomerase I inhibitors such asirinotecan hydrochloride (CAMPTOSAR®, also known as or referred to asCPT 11) (Slichenmyer et al. (1993) J. Natl. Cancer Inst. 85:271-291) andderivatives thereof. Exemplary derivatives of irinotecan include, butare not limited to those described in U.S. Pat. No. 6,403,563; U.S.Patent Application No.: 2001/0056082; U.S. Patent Application No.:2002/00032331; U.S. Pat. No. 6,376,617; U.S. Patent Application No.:2004/0048832; U.S. Pat. No. 6,121,451 U.S. Pat. No. 6,235,907; U.S. Pat.No. 6,444,820, U.S. Pat. No. 6,486,320; U.S. Patent Application No.:2002/0045756; U.S. Pat. No. 6,500,953; EP Patent No.: 0 781 781; EPPatent Application No.: 0 757 049; PCT publication WO 03/074527; and PCTpublication No.: WO 01/30351. The contents of each of the aforementionedpatents and patent applications is hereby expressly incorporated hereinby reference.

Important cancer chemotherapeutic agents (with the usual effectivedosage) to which clinical multidrugresistance has been observed includevinblastine (0.1 mg per kilogram per week), vincristine (0.01 mg perkilogram per week), etoposide (35 to 50 mg per square meter per day),dactinomycin (0.15 mg per kilogram per day), doxorubicin (500 to 600 mgper square meter per week), daunorubicin (65 to 75 mg per square meterper week), and mithramycin (0.025 mg per kilogram per day).

It is well appreciated by those skilled in the field that, at present,there are no effective means of overcoming cellular resistance tochemotherapeutic agents. More importantly there are no practical meansof increasing bioavailability of chemotherapeutics without concomitantincrease in toxicity or side effects. Accordingly, there is arequirement for means of overcoming or at least alleviating the problemsassociated with acquired or inherent cellular resistance as well asmeans of increasing bioavailability of chemotherapeutics.

The applicant has previously investigated the usefulness of hyaluronan(HA) as a drug delivery vehicle for chemotherapeutics, and found that HAwas useful when co-administered with these drugs. International patentapplication no. PCT/AU00/00004 was filed covering this invention, and isincorporated in its entirety herein by reference. HA, also known ashyaluronic acid, is a naturally occurring polysaccharide comprisinglinear-chain polymers, which is found ubiquitously throughout the animalkingdom. HA is highly water-soluble, making it an ideal drug deliveryvehicle for biological systems.

Subsequent to the filing of International patent application no.PCT/AU00/00004, the applicant surprising found that HA could act as asole agent. It was found that HA could exert a cytotoxic effect on humanbreast cancer cells, as well as pre-sensitizing cells so that theybecame more susceptible to chemotherapeutic agents. The presentinvention therefore provides methods whereby cells that were, or hadbecome resistant to chemotherapeutic agents could be effectivelytreated. More importantly, by using the disclosed methods it is possibleto decrease the dosages of chemotherapeutic agents without decreasingthe efficacy to the subject. The methods of the invention includeadministering hyaluronan either alone in conjunction with achemotherapeutic agent.

The present invention is based upon the discovery that hyaluronan,derivatives, analogues, and salts thereof, not only inhibit cells perse, but also allows the safe administration of selected chemotherapeuticagents at standard or lower doses thought to be less effective, to treatsubjects including human subjects. In vivo administration of hyaluronanin combination with chemotherapeutic agents also enhances thetherapeutic effect of these agents against cells that are refractory,thus preventing the subsequent emergence of multidrug resistance.

Diseased cells such as cancer cells often have more permeable membranesdue to an alteration in the membrane potential, or increased receptorstatus which can alter the regulation of their intracellular moleculetransport which can result in cell swelling (Lang et al, 1993). Whilethe applicant does not wish to be bound by any theory they postulatethat there are several mechanisms that could explain the cellular effectthat HA is exerting both as a sole agent, and as a pre-treatment fortherapeutic agents:

1). When HA is bound to CD44, RHAMM and the scavenger receptor bound,the net negative charge of HA alters the membrane potential of the cellresulting in an increase in cell permeability consequently enabling agreater flux of drug into the diseases cell.

2). When HA is bound to diseased cells such as tumour cells andinternalised there could be a hyperosmotic effect resulting in celllysis.

3). HA could exert oxidative membrane damage resulting in apoptosis.

4). HA internalisation could elevate the mitochondrial membranepotential which could result in cell death or increased drug retention.

Since HA is administered at satuarable levels, there would be a constantinternalisation of the glycosaminoglycan which means that anytherapeutic agent which is in an equilibrium within the volumetricdomain of the HA is co-internalised resulting in a concentratedintracellular release of the drug

SUMMARY OF INVENTION

In its broadest aspect the present invention provides a method oftreating a subject in need thereof comprising the step of administeringto said subject a therapeutically effective amount of hyaluronan, or aderivative thereof, in conjunction with a chemotherapeutic agent suchthat said chemotherapeutic agent is more effective than whenadministered alone.

The present invention also provides a method of enhancing thebioavailability of a chemotherapeutic agent comprising the step ofadministering to a subject in need thereof a therapeutically effectiveamount of hyaluronan, or a derivative thereof.

Hyaluronan can be used to significantly enhance the bioavailability ofany administered chemotherapeutic agent. Preferably, thechemotherapeutic agent that is administered is selected from the groupconsisting of irinotecan (Camptosar), carmustine (BCNU), chlorambucil(Leukeran), cisplatin (Platinol), Cytarabine, doxorubicin (Adriamycin),fluorouracil (5-FU), methoxetrate (Mexate), CPT 11 (irinotecan),etoposide, plicamycin (Mithracin) and taxanes such as, for example,paclitaxel.

In yet another embodiment, the invention provides a method of treatingor preventing multidrug resistance or drug-resistant cells comprisingthe step of administering a therapeutically effective amount ofhyaluronan, prior to, together with, or subsequent to the administrationof a chemotherapeutic agent.

As described more fully below, administration of hyaluronan and achemotherapeutic agent results in the suppression of tumor growth by atleast 50%; preferably 60%; more preferably, greater than 70%, and evenmore preferably greater than 80%, 90% or 95%. Accordingly, theelimination of tumor growth and proliferation eliminates the productionof multidrug resistant cells thereby reducing the recurrence of cancerand increasing the efficacy of chemotherapeutic treatments.

The present invention further provides a pharmaceutical composition forincreasing the sensitivity of cells to chemotherapeutic agentscomprising hyaluronan. The hyaluronan and/or chemotherapeutic agent mayalso be administered together with a further pharmaceutical carrier.

The present invention also provides a method of treating cancer cellscomprising the step of administering to a patient in need thereof atherapeutically effective amount of hyaluronan.

Typically said cancer cells are resistant to chemotherapeutic drugs.

In a further aspect of the present invention there is provided a methodof overcoming cellular resistance, comprising the step of administeringa therapeutically effective amount of HA.

In another embodiment, the invention provides compositions comprisinghyaluronic acid and a therapeutically effective amount of achemotherapeutic, e.g., irinotecan or a derivative thereof. In a relatedembodiment, the modal molecular weight of hyaluronic acid is 850,000daltons. In another related embodiment, the therapeutically effectiveamount of the anticancer agent is 50 mg/kg irinotecan.

In another embodiment, the invention provides the for the use of acomposition comprising a therapeutically effective amount of ananticancer agent and hyaluronic acid, or a derivative thereof for thetreatment of cancer. In a related embodiment, the composition compriseshyaluronic acid, or a derivative thereof and irinotecan, or a derivativethereof. In another related embodiment, the composition compriseshyaluronic acid with a modal molecular weight of hyaluronic acid is850,000 daltons. In specific embodiments, the use of the compositionreduces tumor volume by at least 80%, 90% or 95%. In another specificembodiment, the use of the composition results in total tumorregression.

In another embodiment, the invention provides a method of treating asubject having cancer comprising administering to said subject acomposition comprising hyaluronic acid and an effective amount ofirinotecan, thereby treating the subject. In a related embodiment, thecomposition comprises hyaluronic acid, or a derivative thereof andirinotecan, or a derivative thereof. In another related embodiment, thecomposition comprises hyaluronic acid with a modal molecular weight ofhyaluronic acid is 850,000 daltons. In specific embodiments, thehyaluronic acid is administered at a concentration of about 10 mg/kg toabout 150 mg/kg, 25 mg/kg to about 100 mg/kg, or at 50 mg/kg.

Throughout the description and claims of this specification, the word“comprise” and variations of the word, such as “comprising” and“comprises”, means “including but not limited to” and is not intended toexclude other additives, components, integers or steps.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows exponentially growing breast cancer cells exposed to750,000 dalton HA for 24 h at which stage the cells were photographed.At 10 ng/ml there was a reduction in cell number, but no difference inmorphology was noted. At 100 ng/ml and 100 g/ml the cells appeared topbe undergoing a osmotic response where the cells appeared to swell. At 2mg/ml and 5 mg/ml the cells became granular and the plasma membrane was“pitted” possibly indicating an osmotic response and/or the commencementof cell death.

FIG. 2 a-2 f shows exponentially growing breast cancer cells that wereexposed to 750,000 dalton HA for 30 min, 1 h, or 24 h at which stage thecells were varying concentrations of adriamycin. These figures alsoillustrate the effect of HA/drug co-incubation for the period of 1 or 3days. These diagrams illustrate that HA can “pre-sensitise” and/orchemosensitise cells to therapeutic drugs.

FIGS. 3 a-3 d shows exponentially growing breast cancer cells exposed tovarying concentrations of 750,000 dalton hyaluronan for 1 h, 24 h or 3days followed by treatment with 40 nM Adriamycin for varying timeperiods of 1 h, 24 h or 3 days. These figures show that a wideconcentration range of hyaluronan can act as a chemosenitiser or exert acytotoxic effect.

FIG. 4 shows that there was no treatment toxicity noted throughout the6-week study. In comparison to the 5-FU treatment group the micereceiving HA therapy, that is as a sole agent or as a chemosensitizer,demonstrated enhanced well being where the animal did not loose weight,but maintained its body mass.

FIG. 5 shows that at the end of the 6 week study, tumour mass wasdetermined where the HA chemosensitizing therapy had significantlysmaller tumours than the saline group, HA and 5-FU groups (p=0.005). HAas a sole agent also demonstrated its effect by reducing the primarytumour mass in comparison to the saline control. No significantdifferences in tumour response were noted in the initial 2 weeks oftreatment, but thereafter the HA followed by 5-FU tumour growth wasretarded in comparison to the other treatment groups. During the 6 weeksof treatment interesting differences were noted in the number of tumourdoubling cycles. Mice receiving the saline treatment underwent anaverage of 4 tumour doublings, while the incorporation of HA into thetreatment regimen significantly increased the tumour doubling time whereHA/5-FU animals underwent an average of one tumour doubling cycle, onceagain highlighting the effect of HA on 5-FU cytotoxicity.

FIG. 6 shows that the co-administration of HA resulted in a significantreduction in non-lymphoid metastasis. With the exception of the micereceiving the HA therapy, new tumours were observed around the neck orunderarm region of the area adjacent to the primary tumor.

FIG. 7 is a graph showing the comparison of the effect of differentmolecular weights of hyaluronic acid on cell survival of MDA-MB-468.

FIGS. 8A-B are graphs demonstrating the effects of titration ofhyaluronan on breast cancer cell lines. FIG. 8A depicts the effect ofincreasing concentrations of hyaluronan on MDA-MB-435. FIG. 8B depictsthe effect of increasing concentrations of hyaluronan on MDA-MB-468.

FIGS. 9A-B are graphs demonstrating the effects of titration ofhyaluronan effects of hyaluronan in vivo. FIG. 9A depicts the mean tumorvolume as a function of time after administration for saline (opencircles), hyaluronan administered days 1 and 2 of 6xq7D (opentriangles), and hyaluronan administered days 1 and 3 of 6xq7 (closedtriangles).

FIG. 10 is a graph indicating that intravenous hyaluronan forms amicro-embolic drug depot in the vasculature of human breast cancerxenografts. After the intravenous administration of 15 mg/kg of 825 kDa[³H] HA the tumors were homogenized and the cell/tissue extractsanalyzed using size exclusion chromatography. The percentage ofmacromolecular weight HA was calculated as material eluting in the voidvolume of a Superose 12 gel.

FIG. 11A-B are graphs demonstrating the effects of DOX vs. HYDOX™. FIG.11A depicts a graph demonstrating the effects of DOX and HyDOX™ on tumorvolume as a function of the number of cycles of treatment. FIG. 11Bdepicts a bar graph showing the tumor viability in animals treated withDOX or HyDOX™.

FIG. 12 is a graph demonstrating the effect of DOX and HYDOX™ onCD44-negative breast cancer xenographs.

FIG. 13 is a graph demonstrating the effect of DOX, HyDOX™, and Caelyxon CD44-positive breast cancer xenographs.

FIG. 14 is a graph showing the effects of different concentrations ofhyaluronan on the cytotoxicity of doxorubicin. Rat myocardiocytes wereexposed to DOX+10 μM HA, DOX only, DOX+1 μM HA, or DOX+100 nM HA andtheir survival was plotted as a percentage of the control containing nodrug.

FIG. 15 is bar graph demonstrating a comparison of cardiac damage causedby DOX and HyDOX™.

FIGS. 16A-B are graphs demonstrating the toxicity of hyaluronan, DOX andHYDOX™. FIG. 16A depicts the results of the administration of theequivalent of 30 mg/m² DOX clinical dose. The percentage of neutrophilsat Day 0 is plotted against the number of days after administration ofthe indicated compounds. FIG. 16B depicts the results of theadministration of the equivalent of 45 mg/m² DOX clinical dose. Thepercentage of neutrophils at Day 0 is plotted against the number of daysafter administration of the indicated compounds.

DETAILED DESCRIPTION OF THE INVENTION

The methods and compositions of the invention are useful for increasingthe sensitivity of cells to chemotherapeutic agents such as, forexample, anti-cancer agents like paclitaxel or irinotecan, analgesics,opiates, hormones or antibiotics and the like. In particular the methodsand compositions of the invention are useful for increasing thesensitivity of cells associated with cellular proliferative disorders(eg., a neoplasm). By increasing the efficacy without concomitanttoxicity to non-cancer cells the invention provides methods andcompositions useful for treating tumors and preventing or reducing thechances of relapse and death as a result of cytotoxicity. In addition,the invention eliminates or reduces the number of multidrug resistantcells by eliminating cancer cells prior to any mutation inducing amultidrug resistant phenotype. Accordingly, by reducing multi-drugresistant tumor cells from arising, the invention satisfies theshortcomings of current therapeutic modalities.

The term “subject” as used herein refers to any animal having a diseaseor condition which requires treatment with a chemotherapeutic agentwherein the chemotherapeutic agent has reduced efficacy relative to thatdesired. Preferably the subject is suffering from a cellularproliferative disorder (eg., a neoplastic disorder). Subjects for thepurposes of the invention include, but are not limited to, mammals (eg.,bovine, canine, equine, feline, porcine) and preferably humans.

By “cell proliferative disorder” is meant that a cell or cellsdemonstrate abnormal growth, typically aberrant growth, leading to aneoplasm, tumor or a cancer.

Cell proliferative disorders include, for example, cancers of thebreast, lung, prostate, kidney, skin, neural, ovary, uterus, liver,pancreas, epithelial, gastric, intestinal, exocrine, endocrine,lymphatic, haematopoietic system or head and neck tissue.

Generally, neoplastic diseases are conditions in which abnormalproliferation of cells results in a mass of tissue called a neoplasm ortumor. Neoplasms have varying degrees of abnormalities in structure andbehaviour. Some neoplasms are benign while others are malignant orcancerous. An effective treatment of neoplastic disease would beconsidered a valuable contribution to the search for cancer preventiveor curative procedures.

The methods of this invention involve in one embodiment, (1) theadministration of hyaluronan, prior to, together with, or subsequent tothe administration of a chemotherapeutic agent; or (2) theadministration of a combination of hyaluronan and a chemotherapeuticagent.

As used herein, the term “therapeutically effective amount” is meant anamount of a compound of the present invention effective to yield adesired therapeutic response. For example to prevent cancer or treat thesymptoms of cancer in a host or an amount effective to treat cancer.

The specific “therapeutically effective amount” will, obviously, varywith such factors as the particular condition being treated, thephysical condition of the patient, the type of mammal being treated, theduration of the treatment, the nature of concurrent therapy (if any),and the specific formulations employed and the structure of thecompounds or its derivatives.

As used herein, a “pharmaceutical carrier” is a pharmaceuticallyacceptable solvent, suspending agent or vehicle for delivering thehyaluronan and/or chemotherapeutic agent to the animal or human. Thecarrier may be liquid or solid and is selected with the planned mannerof administration in mind.

As used herein, “cancer” refers to all types of cancers or neoplasm ormalignant tumours found in mammals. Cancer includes sarcomas, lymphomasand other cancers. The following types are examples, but are, but is notintended to be limited to these particular types of cancers: prostate,colon, breast, both the MX-1 and the MCF lines, pancreatic,neuroblastoma, rhabdomysarcoma, home, lung, murine, melanoma, leukemia,pancreatic, melanoma, ovarian, brain, head & neck, kidney, mesothelioma,sarcoma, Kaposi's, sarcoma, stomach, and uterine.

As used herein, the term “cell” include but is not limited to mammaliancells (eg., mouse cells rat cells or human cells).

The instant invention also provides compositions including one or morechemotherapeutic agents and derivatives, fragments and/or salts ofhyaluronan (hyaluronic acid). A number of derivatives and fragments ofhyaluronan have been described in the literature and are intended to beincluded in the methods and formulations of the instant invention.

Exemplary hyaluronic acid derivatives are those described in U.S. Pat.No. 6,620,927 (thiol-modified hyaluronic acid derivatives); U.S. Pat.No. 6,552,184 (crosslinked compounds of hyaluronic acid and thederivatives thereof); U.S. Pat. No. 6,579,978 (sulphated compounds ofhyaluronic acid and derivatives thereof); U.S. Pat. No. 6,831,172(cross-linked hyaluronic acids and hemisuccinylated derivates thereof);U.S. Pat. No. 6,027,741 (sulfated hyaluronic acid and esters thereof);European Patent No. 0 138 572 (Hyaluronic acid fragments HYALECTIN andHYALASTINE); U.S. Pat. No. 4,851,521 (hyaluronic acid esters withdifferent aromatic aliphatic and/or araliphatic alcohols); U.S. Pat. No.5,202,431 (partial esters of hyaluronic acid); U.S. Pat. No. 5,676,964(crosslinked hyaluronic acid polymers) and EP 0 265 116 (crosslinkedesters of hyaluronic acid).

In addition to fragments and derivatives of hyaluronic acid, syntheticderivatives, i.e., semisynthetic derivatives may be used in the methodsand compositions of the invention. Exemplary semisynthetic derivativesof hyaluronic acid are esters of hyaluronic acid with alcohols of thealiphatic, araliphatic, heterocyclic and cycloaliphatic series,designated “HYAFF,” that are described in U.S. Pat. Nos. 4,851,521,4,965,353, and 5,202,431, EP 0 341 745 and EP 0 216 453. The contents ofeach of the above-identified patents are expressly incorporated hereinby reference.

The hyaluronan and/or chemotherapeutic agents may be administeredorally, topically, or parenterally in dosage unit formulationscontaining conventional non-toxic pharmaceutically acceptable carriers,adjuvants, and vehicles. The term parenteral as used herein includessubcutaneous injections, aerosol, intravenous, intramuscular,intrathecal, intracranial, intrasternal injection or infusiontechniques.

The present invention also provides suitable topical, oral, andparenteral pharmaceutical formulations for use in the novel methods oftreatment of the present invention. The compounds of the presentinvention may be administered orally as tablets, aqueous or oilysuspensions, lozenges, troches, powders, granules, emulsions, capsules,syrups or elixirs. The composition for oral use may contain one or moreagents selected from the group of sweetening agents, flavouring agents,colouring agents and preserving agents in order to producepharmaceutically elegant and palatable preparations. The tablets containthe active ingredient in admixture with non-toxic pharmaceuticallyacceptable excipients which are suitable for the manufacture of tablets.

These excipients may be, for example, (1) inert diluents, such ascalcium carbonate, lactose, calcium phosphate or sodium phosphate; (2)granulating and disintegrating agents, such as corn starch or alginicacid; binding agents, such as starch, gelatin or acacia; and lubricatingagents, such as magnesium stearate, stearic acid or talc. These tabletsmay be uncoated or coated by known techniques to delay disintegrationand absorption in the gastrointestinal tract and thereby provide asustained action over a longer period. For example, a time delaymaterial such as glyceryl monostearate or glyceryl distearate may beemployed. Coating may also be performed using techniques described inthe U.S. Pat. Nos. 4,256,108; 4,160,452; and 4,265,874 to form osmotictherapeutic tablets for control release.

The hyaluronan as well as the chemotherapeutic agents useful in themethod of the invention can be administered, for in vivo application,parenterally by injection or by gradual perfusion over timeindependently or together. Administration may be intravenously,intraperitoneally, intramuscularly, subcutaneously, intracavity, ortransdermally. For in vitro studies the agents may be added or dissolvedin an appropriate biologically acceptable buffer and added to a cell ortissue.

Preparations for parenteral administration include sterile aqueous ornon-aqueous solutions, suspensions, and emulsions. Examples ofnon-aqueous solvents are propylene glycol, polyethylene glycol,vegetable oils such as olive oil, and injectable organic esters such asethyl oleate. Aqueous carriers include water, alcoholic/aqueoussolutions, emulsions or suspensions, including saline and bufferedmedia. Parenteral vehicles include sodium chloride solution, Ringer'sdextrose, dextrose and sodium chloride, lactated Ringer's intravenousvehicles include fluid and nutrient replenishers, electrolytereplenishers (such as those based on Ringer's dextrose), and the like.Preservatives and other additives may also be present such as, forexample, anti-microbials, anti-oxidants, chelating agents, growthfactors and inert gases and the like.

It is envisioned that the invention can be used to treat pathologiesassociated cell proliferative disorders, including, for example,neoplasms, cancers (eg., cancers of the breast, lung, prostate, kidney,skin, neural, ovary, uterus, liver, pancreas, epithelial, gastric,intestinal, exocrine, endocrine, lymphatic, haematopoietic system orhead and neck tissue), fibrotic disorders and the like.

The methods and compounds of the invention may also be used to treatother diseases associated with chemotherapeutic treatment such asneurodegenerative disorders, hormonal imbalance and the like. Therefore,the present invention encompasses methods for ameliorating a disorderassociated with cell proliferation, neoplasms, cancers and the like,including treating a subject having the disorder, at the site of thedisorder, with hyaluronan and a chemotherapeutic agent in an amountsufficient to inhibit or ameliorate the cell's proliferation or thedisorder. Generally, the terms “treating”, “treatment” and the like areused herein to mean affecting a subject, tissue or cell to obtain adesired pharmacologic and/or physiologic effect. The effect may beprophylactic in terms of completely or partially preventing a cellproliferative disorder or sign or symptom thereof, and/or may betherapeutic in terms of a partial or complete cure for a disorder and/oradverse effect attributable to, for example, aberrant cellproliferation. “Treating” as used herein covers any treatment of, orprevention of a cell proliferative disorder in a vertebrate, a mammal,particularly a human, and includes: (a) preventing the disorder fromoccurring in a subject that may be predisposed to the disorder, but hasnot yet been diagnosed as having it; (b) inhibiting the disorder, i.e.,arresting its development; or (c) relieving or ameliorating thedisorder, i.e., cause regression of the disorder.

The invention includes various pharmaceutical compositions useful forameliorating cell proliferative disorder, including neoplasms, cancersand the like. The pharmaceutical compositions according to oneembodiment of the invention are prepared by bringing hyaluronan,analogue, derivatives or salts thereof and one or more chemotherapeuticagents or combinations of hyaluronan and one or more chemotherapeuticagents into a form suitable for administration to a subject usingcarriers, excipients and additives or auxiliaries. Frequently usedcarriers or auxiliaries include magnesium carbonate, titanium dioxide,lactose, mannitol and other sugars, talc, milk protein, gelatin, starch,vitamins, cellulose and its derivatives, animal and vegetable oils,polyethylene glycols and solvents, such as sterile water, alcohols,glycerol and polyhydric alcohols. Intravenous vehicles include fluid andnutrient replenishers. Preservatives include antimicrobial,anti-oxidants, chelating agents and inert gases. Other pharmaceuticallyacceptable carriers include aqueous solutions, non-toxic excipients,including salts, preservatives, buffers and the like, as described, forinstance, in Remington's Pharmaceutical Sciences, 15th ed. Easton: MackPublishing Co., 1405-1412, 1461-1487 (1975) and The National FormularyXIV., 14th ed. Washington: American Pharmaceutical Association (1975),the contents of which are hereby incorporated by reference. The pH andexact concentration of the various components of the pharmaceuticalcomposition are adjusted according to routine skills in the art. SeeGoodman and Gilman's The Pharmacological Basis for Therapeutics (7thed.).

The pharmaceutical compositions are preferably prepared and administeredin dose units. Solid dose units are tablets, capsules and suppositories.For treatment of a subject, depending on activity of the compound,manner of administration, nature and severity of the disorder, age andbody weight of the subject, different daily doses can be used. Undercertain circumstances, however, higher or lower daily doses may beappropriate. The administration of the daily dose can be carried outboth by single administration in the form of an individual dose unit orelse several smaller dose units and also by multiple administration ofsubdivided doses at specific intervals.

The pharmaceutical compositions according to the invention may beadministered locally or systemically in a therapeutically effectivedose. Amounts effective for this use will, of course, depend on theseverity of the disease and the weight and general state of the subject.Typically, dosages used in vitro may provide useful guidance in theamounts useful for in situ administration of the pharmaceuticalcomposition, and animal models may be used to determine effectivedosages for treatment of particular disorders. Various considerationsare described, eg., in Langer, Science, 249: 1527, (1990). Formulationsfor oral use may be in the form of hard gelatin capsules wherein theactive ingredient is mixed with an inert solid diluent, for example,calcium carbonate, calcium phosphate or kaolin. They may also be in theform of soft gelatin capsules wherein the active ingredient is mixedwith water or an oil medium, such as peanut oil, liquid paraffin orolive oil.

Aqueous suspensions normally contain the active materials in admixturewith excipients suitable for the manufacture of aqueous suspension. Suchexcipients may be (1) suspending agent such as sodium carboxymethylcellulose, methyl cellulose, hydroxypropylmethylcellulose, sodiumalginate, polyvinylpyrrolidone, gum tragacanth and gum acacia; (2)dispersing or wetting agents which may be (a) naturally occurringphosphatide such as lecithin; (b) a condensation product of an alkyleneoxide with a fatty acid, for example, polyoxyethylene stearate; (c) acondensation product of ethylene oxide with a long chain aliphaticalcohol, for example, heptadecaethylenoxycetanol; (d) a condensationproduct of ethylene oxide with a partial ester derived from a fatty acidand hexitol such as polyoxyethylene sorbitol monooleate, or (e) acondensation product of ethylene oxide with a partial ester derived fromfatty acids and hexitol anhydrides, for example polyoxyethylene sorbitanmonooleate.

The pharmaceutical compositions may be in the form of a sterileinjectable aqueous or oleagenous suspension. This suspension may beformulated according to known methods using those suitable dispersing orwetting agents and suspending agents which have been mentioned above.The sterile injectable preparation may also a sterile injectablesolution or suspension in a non-toxic parenterally-acceptable diluent orsolvent, for example, as a solution in 1,3-butanediol. Among theacceptable vehicles and solvents that may be employed are water,Ringer's solution, and isotonic sodium chloride solution. In addition,sterile, fixed oils are conventionally employed as a solvent orsuspending medium. For this purpose, any bland fixed oil may be employedincluding synthetic mono- or diglycerides. In addition, fatty acids suchas oleic acid find use in the preparation of injectables.

Hyaluronan together with a chemotherapeutic agent of the presentinvention may also be administered in the form of liposome deliverysystems, such as small unilamellar vesicles, large unilamellar vesicles,and multilamellar vesicles. Liposomes can be formed from a variety ofphospholipids, such as cholesterol, stearylamine, orphosphatidylcholines.

Dosage levels of the compounds of the present invention are of the orderof about 0.5 mg to about 10 mg per kilogram body weight, with apreferred dosage range between about 5 mg to about 20 mg per kilogrambody weight per day (from about 0.3 gms to about 1.2 gms per patient perday). The amount of active ingredient that may be combined with thecarrier materials to produce a single dosage will vary depending uponthe host treated and the particular mode of administration. For example,a formulation intended for oral administration to humans may containabout 5 mg to 1 g of an active compound with an appropriate andconvenient amount of carrier material which may vary from about 5 to 95percent of the total composition. Dosage unit forms will generallycontain between from about 5 mg to 500 mg of active ingredient.

It will be understood, however, that the specific dose level for anyparticular patient will depend upon a variety of factors including theactivity of the specific compound employed, the age, body weight,general health, sex, diet, time of administration, route ofadministration, rate of excretion, drug combination and the severity ofthe particular disease undergoing therapy.

In addition, some of the compounds of the instant invention may formsolvates with water or common organic solvents. Such solvates areencompassed within the scope of the invention.

The compounds of the present invention may additionally be combined withother compounds to provide an operative combination. It is intended toinclude any chemically compatible combination of chemotherapeuticagents, as long as the combination does not eliminate the activity ofthe hyaluronan of this invention.

The invention will now be further described by way of reference only tothe following non-limiting examples. It should be understood, however,that the examples following are illustrative only, and should not betaken in any way as a restriction on the generality of the inventiondescribed above. In particular, while the invention is described indetail in relation to cancer, it will be clearly understood that thefindings herein are not limited to treatment of cancer. For example, HAmay be used for treatment of other conditions.

EXAMPLES Example 1 Preparation of Hyaluronan and 5-FluorouracilSolutions

HA used in all of the in vitro and in vivo studies were obtained fromKyowa Hakko Kogyo (Yamaguchi, Japan). 5-FU was obtained from Sigma, St.Louis, USA. And Adraimycin from cytomix, Northcote, Melbourne,Australia. A standard profile of the HA used is shown in Table 1.

TABLE 1 Specification Sheet For Hyaluronan Bulk Dried Powder TESTSPECIFICATION  1. Description White or cream coloured powder orgranules, odorless  2. Identification (IR Spectrum) Conforms toReference Standard  3. pH (1% solution) 5.0 to 7.0  4. Loss on DryingNMT 10.0%  5. Residue on Ignition 15.0 to 19.0%  6. Protein Content NMT0.1%  7. Heavy Metals NMT 20 ppm  8. Arsenic NMT 2 ppm  9. SodiumHyaluronate Assay 97.0-102.0% (dried basis) 10. Intrinsic Viscosity10.0-14.5 dL/g 11. Total Aerobic Microbial Count NMT 50 CFU/gram    (USP23) 12. Staphylococcus aureus (USE) 23) Absent 13. Pseudomonasaeruginosa (USP 23) Absent 14. Yeasts and Moulds (USP 23) NMT 50CFU/gram 15. Bacterial Endotoxin NMT 0.07 EU/mg    (LAL)(USP23)

A 10 mg/ml stock of HA solution was prepared by dissolving desiccated HA(modal M_(r) 7.5×10⁵ Da,) in pyrogen-free injection grade water. Toensure a homogenous solution the HA was dissolved overnight at 4° C.followed by thorough vortexing. To ensure that the HA had maintained itsmolecular weight during the preparation of the stock solution, thesolution was analyzed on a Sephacryl S-1000 size exclusion gel withcolumn specifications of 1.6 cm×70 cm, sample size 2 ml, flow rate 18ml/h and 2 ml fraction size. Hyaluronan was detected in column fractionsby the uronic acid assay.

The uronic acid assay was used to detect the presence of hyaluronanqualitatively from the fractions collected from the gel filtrationchromatography procedure. A 25 μl aliquot of each fraction was thentransferred into a 96 well plate. 25011 of a carbazole reagent (3Mcarbazole/0.025M borate in H₂SO₄) was then added to these fractions. The96 well plate was incubated for 45-60 min at 80° C. A Dynatech MR7000plate reader with a 550 nm filter was used to read the 96 well plate.The absorbance was considered to be significant when it was >3 standarddeviations above the background absorbance. The background wascalculated by taking an equal number of sample points before and afterV_(o) and V_(t) where the average number taken was 16 (Fraser et al.1998).

A stock solution of 5-FU was prepared by dissolving powdered 5-FU in 0.1M NaOH (pH 8.9) and brought to a concentration of 1 mg/ml withpyrogen-free injection grade 0.9% w/v NaCl. The stock solution wasfiltered through a 0.22 μm filter to ensure sterility. The 5-FU wasdiluted by adding the required volume of stock solution to the cell-linespecific growth medium as specified above.

A 10 mg/ml solution of adriamycin in 0.9% NaCl was obtained fromCytomix.

Example 2 Testing the Effect of Hyaluronan on Cancer Cell Morphology

Human breast adenocarcinoma cell lines MDA-MB-468, MDA-MB-435 andMDA-MB-231 were selected based on HA binding affinity (Culty et al,1994), and the expression of the HA receptors of CD44 and RHAMM (Wang etal, 1996). The characteristics of these cell lines are shown in Table 2.

TABLE 2 Hyaluronan Binding And Receptor Expression Of Human MammaryCarcinoma Cell Lines HA Receptor Type of breast Degree of HAExpression^(b) Cell Line cancer Binding^(s) CD44 RHAMM MDA-MB-231adenocarcinoma ++ +++ +++ MDA-MB-468 adenocarcinoma ++++ ++++ ++MDA-MB-435 ductal + +++ ND carcinoma a: Culty et al, 1994 ^(b)Wang etal, 1996

Cell lines MDA-MB-468, MDA-MB-435 and MDA-MB-231 were routinely grownand subcultured as a monolayer in 175 cm² culture flasks in LeibovitzL-15 Medium supplemented with 10% Foetal calf serum (FCS) andantibiotic/antimycotic reagents at 37° C. in humidity controlledincubator with 100% (v/v) air.

Leibovitz-L-15 with glutamine (10× concentrate), RPMI (10× concentrate),Eagles basal medium (EBM, 10× concentrate), 20 mM HEPES, 0.09% w/vbicarbonate, Hanks' Balanced Salt Solution (HESS, 10× concentrate) andDulbecco's Phosphate Buffered Saline without calcium and magnesium (PBS,10× concentrate) were purchased from Sigma (St Louis, Mo., USA). Powderconcentrates were dissolved in the required volume of reverse osmosisdeionised pyrogen-free distilled water to make a single strengthsolution, sterilized by 0.22 μm high pressure filtration (MilliporeCorporation, MA. U.S.A.), and stored at 4° C. FCS) were purchased fromthe CSL Ltd., Australia. FCS was stored at −20° C.Antibiotic/antimycotic solution (100× concentrate) containing 10,000units penicillin, 10 mg streptomycin and 25 μg amphotericin U/ml wasobtained from, Sigma (St Louis, USA). Trypsin/EDTA solution (1O×concentrate) containing 5 g porcine trypsin and 2 g EDTA/L in 0.9% w/vsodium chloride was obtained from Sigma (St Louis, Mo., USA). All breastcancer cell lines were purchased from American tissue culture collection(Rockville, USA). All plastic disposable culture vessels were purchasedfrom Greiner (Austria). Eight-welled, tissue culture microscope slideswere obtained from Linbro (Flow Laboratories, VA, USA).

For the tests, MDA MB-468, MDA MB-231 and MDA MB-435 cell line weregrown in 90% Leibovitz L-15 medium supplemented with 10% FCS. Whenconfluent the cultures were washed 1× in HBSS and trypsinised in 0.25%trypsin/0.05% EDTA. The cell suspensions were counted with an automatedcell counter (ZM-2 Coulter Counter) by adding 15 mL saline+0.2 ml ofcell suspension.

Cells were resuspended to a number of:

-   -   MDA MB-468: 25,000 cell/ml of media    -   MDA MB-231: 12,000 cell/ml of media    -   MDA MB-435: 12,000 cell/ml of media

The cells were plated into 48-well plates (1 cm² surface area) by adding1 ml of cell suspension per well.

Cells were allowed to attach for 24 h, before the media was removed,monolayers washed. The test media was; growth media containing 0-1 μMadriamycin or 5-fluorouracil with or without the addition of 0-1 μM ofHA (modal Mw 750,000).

The cells were exposed to the several combinations of HA and drugs fordifferent times and at different concentrations (Table 3).

TABLE 3 Incubation Conditions for Hyaluronan and Drugs with Human BreastCancer Cells HA Drug Growth Sequence of HA/Drug Addition IncubationIncubation Time 0-1 μM HA, media wash, 0-1 μM 30 min  1 h  1 day drug,media wash, grow drug- free 0-1 μM HA, media wash, 0-1 μM  1 h  1 h  1day drug, media wash, grow drug- free 0-1 μM HA, media wash, 0-1 μM 24 h 1 h  1 day drug, media wash, grow drug- free 0-1 μM HA, media wash, 0-1μM 24 h 24  1 day drug, media wash, grow drug- free 0-1 μM HA, mediawash, 0-1 μM 30 min  1 h  3 day drug,. media wash, grow drug- free 0-1RM HA, media wash, 0-1 μM  1 h  1 h  3 day drug, media wash, grow drug-free 0-1 μM HA, media wash, 0-1 μM 24 h  1 h  3 day drug, media wash,grow drug- free 0-1 μM HA, media wash, 0-1 μM 24 h 24  3 day drug, mediawash, grow drug- free 0-1 μM drug/100 nM HA 30 min  1 day 0-1 μMdrug/100 nM HA  1 h  1 day 0-1 μM drug/100 nM HA 24  1 day 0-1 μMdrug/100 nM HA 30 min  3 days 0-1 μM drug/100 nM HA  1 h  3 days 0-1 μMdrug/100 nM HA 24  3 days 0-1 μM HA 30 min  1 day 0-1 μM HA  1 h  1 day0-1 μM HA 24  1 day 0-1 μM HA 30 min  3 days 0-1 μM HA  1 h  3 days 0-1μM HA 24  3 days 0-1 μM HA  3 days  3 days

After the incubation and growth periods the cell monolayers were washedwith HBSS and trypsinised in 0.25% trypsin/0.05% EDTA. The cellsuspensions were counted with an automated cell counter (ZM-2 CoulterCounter) by adding 15 mL saline+0.2 ml of cell suspension. Results wereexpressed as % of no drug control which was calculated as:

$\frac{{Cell}\mspace{14mu}{count} \times 100}{{Cells}\mspace{14mu}{in}\mspace{14mu}{no}\mspace{14mu}{drug}\mspace{14mu}{control}}$Or depending on the experiment as % of drug control, calculated as:

$\frac{{Cell}\mspace{14mu}{count} \times 100}{{Cells}\mspace{14mu}{in}\mspace{14mu}{drug}\mspace{14mu}{control}}$

Exponentially growing human breast cancer cells MDA MB 231 as describedin example 2 were incubated with 0-5 mg/ml HA (modal Mr 750,000 D) for24 h. At 24 h the cells were counted and photographed with CPR, 1600film rolls from Eastman Kodak Company, Rochester, USA.

When HA was incubated with breast cancer cells for 30 min, 1 h, 24 h or3 days a varied response was observed, where the reduction in breastcancer cell number ranged from 0-29% (See Table 4).

TABLE 4 Cytotoxic Effect of HA on Human Breast Cancer Cell LinesExposure Cell Line Cell Line Cell Line Time MDA-MB MDA-MB 231 MDA-MB 435 3 days 100 nM −29% −23% −22%  1 h 100 nM +3% −21%  −4% 30 min 100 nM−5% −27% −12% 30 min 500 nM −22%  0  30 min 1000 nM +2% −26% ND 24 h 100nM −5% −8% −12% *Figures are the mean of 2-3 separate determinations

When human breast cancer cells were incubated with HA specificmorphological changes (See FIG. 1) were also observed such as swellingof the plasma membrane, greater granularity of cytosolic components.

When human breast cancer cells were exposed to HA for 30 min, 1 h, 24 hor 3 days followed by exposure to adriamycin, it became evident that HAenhanced the cytotoxicity of the drug (FIG. 3 & Table 5).

TABLE 5 Effect of HA on Adriamycin Cytotoxicity in Breast Cancer CellLines IC₅₀ IC₅₀ IC₅₀ Treatment MDA-MB 468 MDA-MB 231 MDA-MB 435  3 daydrug 3 to 12 4 to 5 10 exposure  1 h drug/HA, 3 40 2 to 8  0 daysdrug-free  1 h drug, 3 days 20 to 40  3 to 9  6 to 10 drug-free 30 min100 nM HA, 2 to 20 2 to 6  4 to 40 1 hr drug, 3 days drug-free 30 min100 nM HA, 3 to 18 2 to 4 2 to 8 3 day drug exposure 30 min 500 nM HA, 3to 9  2 to 8 2 to 4 3 day drug exposure 30 min 1000 nM HA, 1 to 10 2 to8 1 to 5 3 day drug exposure 24 h 100 nM HA, 3 8 to 12 13 24 day drugexposure 24 h 100 nM HA, 1 h 50 to 60   9 21 drug exposure, drug-free 3daysAll figures represent the range of 2-3 separate experiments, where thenumerical values are the multiplication factor decrease in IC₅₀ which isexerted by the addition of HA to drug or pre-sensitization of cancercells with HA before the addition of drug.

Example 3 Efficacy of Hyaluronan In Vivo

Based on the results from the in vitro drug sensitivity experiments inExample 2, evaluation of the treatment efficacy of hyaluronan as a soleagent, and as a chemosensitizer in the treatment human breast carcinomasin vivo was undertaken.

From the results in Example 2 the carcinoma cell line MDA-MB-468 wasselected as the cancer cell inoculant for the generation of any nudemouse human tumour xenografts. Cells were routinely grown andsubcultured as a previously described in Example 2. For injection intomice, cells were grown to 100% confluency, trypsinised in 0.025%trypsin/0.01% EDTA solution, washed twice by centrifugation in a BeckmanTJ-6 bench centrifuge at 400 g_(av) for 10 min, counted using a Model-ZMCoulter counter and resuspended in serum-free Leibovitz L-15 medium at1×10⁸ cells/ml.

Six to eight weeks old athymic CBA/WEHI nude female mice, purchased fromthe Walter and Eliza Hall Research Institute, Melbourne Australia, weremaintained under specific pathogen-free conditions, with sterilized foodand water available ad libitum. Each mouse received one injectioncontaining 5×10⁶ cells in 50 μl. The cells were injected with a 26 gaugeneedle into the mammary fat pad directly under the first nipple (Lamszuset al, 1997). Tumour measurements were made weekly by measuring threeperpendicular diameters (d₁d₂d₃). Tumour volume was estimated using theformula:(⅙)π(d₁d₂d₃)

Treatment with 5-FU±HA was commenced approximately 4-8 weeks after thecancer cell inoculation. The mean tumour size for mice used in eachstudy is summarized in Table 6.

TABLE 6 Summary of Human Breast Cancer Tumours at Commencement of EachStudy Tumor volume Tumour as % of net body Study (mean ± SEM) mass (mean± SEM) Efficacy: 6- 0.37 ± 300.20 mm³ 0.19 ± 0.10 mm³ week

Approximately 8 weeks after tumour induction two tumour-bearing micewere given a lethal dose of Nembutal. Within 3 min of killing the mice,tumours were surgically removed and immediately fixed in 10% bufferedformalin for 12 h. The fixed tumour was dehydrated overnight in a seriesof 70-100% ethanol, followed by paraffin embedding from which 2-4 μmsections were cut. The sections were placed on slides, de-waxed, andbrought to water. Slides were washed 3×5 min in PBS. Heterophileproteins were blocked by incubation with 10% foetal calf serum for 10min, followed by a PBS rinse.

Secondary antibodies used in the visualization of HA and HA synthaseantibodies were purchased from Dako (California, U.S.A.).3,3′-Diaminobenzidine (Sigma Fast DAB) tablets were obtained from Sigma,St. Louis, USA.

The detection antibodies were applied for 60 min at RT. The detectionantisera or antibodies were against RHAMM, CD44H and CAE. The slideswere washed 3×5 min in PBS and endogenous peroxidase activity blocked byimmersion in 0.3% H₂O₂ in methanol for 20 min. Following a further PBSwash, the peroxidase-conjugated swine anti-rabbit secondary antiserumwas applied for 60 min at RT, followed by 3×5 min washes in PBS. SigmaFast 3,3′-Diaminobenzidine tablets (DAB) were prepared according to themanufacturer's instructions and the DAB solution was applied for 5-10min at RT. The slides were washed in tap water for 10 min,counterstained with haematoxylin, dehydrated and mounted.

Individual injections of 5-FU were prepared according to individualmouse masses, with the aim of delivering 30 mg/kg 5-FU in 50 μl(equivalent to human therapeutic dose of 10.5 mg/kg for a mean bodyweight of 60 kg; Inaba et al, 1988). HA injection comprising a final HAconcentration equivalent to 12.5 mg/kg of mouse mass were prepared sothat deliver of 12.5 mg/kg HA in 50 μl could be effected. With thisquantity of HA injected into the body, saturation kinetics would beobserved for the period of the experimentation (Fraser et al, 1983).

One of the most commonly used treatment regimens for human breast canceris cyclophosphamide, methotrexate and 5-fluorouacil, which isadministered on day 1 and 8 of a 28 day cycle. In human breast cancerthe initial treatment regimen is for 6 cycles at which time the patientcondition is re-assessed, therefore we tried to simulate the humantreatment regimen as closely as possible by exposing the mice to 6cycles (6 months) of treatment in a long term efficacy study and a 6cycles (6 week) short term efficacy study. Considering the life cycle ofa mouse is approximately 2 years we commenced both short-term andlong-term treatment protocols (see Table 7).

TABLE 7 Treatment Administration Protocols. 6-Week Study TreatmentRegimen Bolus Treatment Group Dosage injection on Days 1. Saline 0.1 mlof 0.9% 1 & 2 of 7 day cycle saline (injection grade) 2. HA 0.1 mlcontaining: 1 & 2 of 7 day cycle 12.5 mg/kg HA 3. 5-FU 0.1 mlcontaining: 1 & 2 of 7 day cycle 30 mg/kg 5-FU 4. HA followed 0.1 mlcontaining: 1: HA    by 5-FU 12.5 mg/kg HA or 2: 5-FU 30 mg/kg 5-FU 3:HA 4: 5-FU of 7 day cycle 5. HA 0.1 ml containing: 1: HA 12.5 mg/kg HA3: HA of 7 day cycle 6. 5-FU 0.1 ml containing: 2: HA 30 mg/kg 5-FU 4:HA of 7 day cycle

Mice were randomly divided into 7 groups of 8 animals per group for theshort term study and 5 groups of 8 animals for the long term study(refer to Table 7 for dosage and treatment administration schedule).

The treatment was not extended over the 6 month regimen since it hasbeen demonstrated that chemotherapy lasting more than six months has notgenerally been associated with greater benefit (Harris et al, 1992).

Animals were weighed and tumour volumes measured on the day of treatmentapplication for long term study. In the 6-week study animals wereweighed and tumour volumes measured on a daily basis. Animals wereindividually placed in an injection box, and the injections wereadministered via the tail vein. It has been experimentally proven thatstress can be a major factor in a patients response to chemotherapy(Shackney et al, 1978), therefore we ensured that equal numbers of micewere allocated to each cage, the animal number per cage varied from 5-8depending on the stage of experimentation.

The experimental end-point occurred when the animal had to be euthaniseddue to degree of disease progression or when the 6 month (long term) or6 week (short term) treatment regimen was completed. Due to the animalethics guidelines the animals were monitored fortnightly by anindependent animal ethics officer who assessed the degree of diseaseprogression. The following criteria were used to determine if an animalhad reached the stage of experimental end-point of necessary death:

-   -   1). Tumour mass was so large the animal was immobilized;    -   2). Animal was not eating or drinking and had experienced        dramatic weight loss; or    -   3). Tumour size was greater than 10% of body mass.

At the experimental end-point the animals were anaesthetized by a 0.1 mlintra-peritoneal injection of Nembutal (60 mg/ml), blood was collectedfollowed by killing of the animals using cervical dislocation.

Immediately after killing the mouse the tumour, liver, heart, spleen,bladder, left and right kidneys, uterus, lungs, stomach, intestines,brain and lymph nodes were excised and placed in 4% formalin bufferedwith 0.06M phosphate pH 7.5, and cetylpyridinium chloride, 1.0% w/v. Thetissue was fixed for 16-24 h before histological processing. Fixedtissue was dehydrated stepwise to 100% ethanol and embedded in paraffinblocks from which 2-4 μm sections were placed on glass microscopeslides. Staining the tissue sections with a haematoxylin nuclear stainand eosin cytoplasmic stain highlighted any pathological features thatcould indicate treatment toxicity.

Nine to 11 lymph nodes were collected per animal, ensuring that allnodes which drained the tumour area were collected. There are currentlytwo methods used for the detection of lymph node metastasis

-   -   i) routine haematoxylin and eosin staining of gross organ        structure; and    -   ii) immunohistochemistry using a cancer marker 20 such as        carcinoembryonic antigen.

Both methods of metastasis detection were employed in this study. Notall commercially available CEA antibodies react with human breast cancercells, so we tested the reactivity of 5 different antibodies (DAKO,Amersham and KPL).

The haematoxylin and eosin stained lymph nodes were examined by Dr P.Allen (certified pathologist) where each node was microscopicallyexamined for the presence of tumour cells. The CEA immunostained lymphnodes were microscopically examined, where any positively stained nodeswere counted and considered positive for lymph node metastasis.

Tumour volume was monitored on a daily or weekly basis by calipermeasurements and tumour volume calculated as previously described. Atthe end of the 6 week study, tumour mass was determined where the HAchemosensitizing therapy had significantly smaller tumours than thesaline group, HA and 5-FU groups (p=0.005) as see in FIG. 5. Nosignificant differences in tumour response were noted in the initial 2weeks of treatment, but thereafter the HA followed by 5-FU tumour growthwas retarded in comparison to the other treatment groups. During the 6weeks of treatment interesting differences were noted in the number oftumour doubling cycles. Mice receiving the saline treatment underwent anaverage of 4 tumour doublings, while the incorporation of HA into thetreatment regimen significantly increased the tumour doubling time whereHA/5-FU animals underwent an average of one tumour doubling cycle, onceagain highlighting the effect of HA on 5-FU cytotoxicity.

All animals displayed lymph node metastasis in lymph nodes that wereadjacent to the primary tumour. The percentage of lymph node involvement(number of metastatic nodes per animal) was greatly reduced by the HAfollowed by 5-FU, 5-FU and HA treatment, where the saline groupdemonstrated a 6-fold increase in the amount of lymph node involvement.The other treatment groups demonstrated a significantly smallerpercentage at 12.2-14.3% (Dunnett's Multiple Comparison Test, p=<0.001).

The co-administration of HA resulted in a significant reduction innon-lymphoid metastasis. With the exception of the mice receiving the HAtherapy, new tumours were observed around the neck or underarm region ofthe area adjacent to the primary tumour.

Gastro-Intestinal Tract Toxicity:

One of the most common toxic effects of 5-FU is on the gastro-intestinaltract where haemorrhagic enteritis and intestinal perforation can occur(Martindale, 1993). Animals were monitored daily for GI tract upset suchas diarrhea and weekly for more severe toxicity manifestations such asweight loss. Weight loss was monitored by calculating net body weight asestimated by subtracting tumour weight, which was calculated as 1g×tumor volume (cm³) as cited in Shibamoto et al, 1996. Fordemonstration of any weight changes the animal body weight wasnormalized to the body weight at the time of treatment commencement as

$\frac{\begin{matrix}{{{Body}\mspace{14mu}{{mass}\left( {{ex}\mspace{14mu}{tumour}} \right)}} -} \\{{body}\mspace{14mu}{mass}\mspace{14mu}{at}\mspace{14mu}{commencement}\mspace{14mu}{of}\mspace{14mu}{{treatment}\left( {{ex}\mspace{14mu}{tumour}} \right)}}\end{matrix}}{{Body}\mspace{14mu}{mass}\mspace{14mu}{at}\mspace{14mu}{commencement}\mspace{14mu}{of}\mspace{14mu}{{treatment}\left( {{ex}\mspace{14mu}{tumour}} \right)} \times 100}$

No treatment toxicity was noted throughout the 6-week study. Incomparison to the 5-FU treatment group the mice receiving HA therapy,that is as a sole agent or as a chemosensitizer, demonstrated enhancedwell being where the animal did not loose weight, but maintained itsbody mass (FIG. 4).

Blood Marrow Suppression

As one of the major toxicities associated with 5-FU treatment isdepression of the bone marrow and subsequent drop in white blood cellsit was necessary to assess any treatment associated blood toxicity. Uponanaesthetizing the animals, blood was collected from the heart or greatvessels using a needle and syringe. Estimation of white blood cellnumber by making a 1/50 dilution of blood in mouse tenacity saline (M)and counting it on a haemocytometer. A differential blood count wasperformed by counting-neutrophils, lymphocytes, and erythrocytes. Thetotal estimation of blood cell sub-populations was compared to publisheddata for mouse blood.

The total white cell count and sub-population differential were notsignificantly different, regardless of the treatment.

Effect of Treatment on Organ Mass

To ensure that treatments did not induce organ atrophy or enlargement,the organs were removed and weighed during the post mortem. The mass ofeach organ was calculated as a % of the overall net body weight, andcompared to the organ masses of the saline only group (Group 1).

The overall patient survival time was calculated as the time (days orweeks) that the animal lived after the commencement of treatment. Allanimals in each treatment group completed the 6-week treatment program.

In relation to organ mass, the HA therapy did not result in any dramatictoxicity. Mice receiving 5-FU exhibited an enlarged spleen (61% increasein mass), while the co-administration of HA and 5-FU significantlycounteracted this enlargement by 31% (student t-test, p<0.001). The 5-FUtherapy resulted in a shrinkage of the uterus (22%), once again theHA/5-FU therapy reduced this toxic effect by 10% (student t-test,p=0.04). It was also clearly defined that the addition of HA to thetreatment regimen, when co-administered or administered the day before,significantly decreased the primary tumour mass in comparison to thesaline treatment group (student t-test, p=0.006). No other differencesin organ mass were noted between treatments.

Example 4 Effect of Hyaluronan Concentration on the In Vitro Efficacy of5-FU

MDA-MB 468, MDA-MB 435 and MDA-MB 231 cells were cultured as describedin Example 0.2. When the cultures had reached 70-80% confluency theywere washed in 1×HBSS at 37° C. and trypsinised in 10 ml of 0.25%trypsin/0.05% EDTA until cells have fully detached. After add 1 ml ofFCS to neutralize trypsin the cells were counted, centrifuged at 1,200rpm for 5 min and resuspended as follows:

-   MDA-MB 231: 12,000 cells/ml of media;-   MDA-MB 468: 25,000 cells/ml of media; and-   MDA-MB 435: 12,000 cells/ml of media.    Cells were then plated into 48-well plates and incubated in    accordance with suppliers' instructions. After 24 h media was    removed and replaced with the following test media:-   MDA-MB 468: 40 nM adriamycin;-   MDA-MB 231: 50 nM adriamycin; and-   MDA-MB 435: 10 nM adriamycin-   40 nM Adriamycin media: 450 ml (Stock adriamycin is 1.7 mM,    therefore 1,700,000/40=42,500; 450,000/42500=10.6 ul of 1.7 mM    Adriamycin+450 ml Media).-   Stock HA was 750,000 daltons at 14.3 M HA    Conclusions

This study has definitively proven that HA, can enhance the cytotoxicityof anti-cancer drugs, 5-FU and Adriamycin, both in vitro and in vivo.More specifically:

-   -   1). As a sole agent HA can exert a cytotoxic effect on cancer        cells both in vitro and in vivo (FIG. 5);    -   2). Evaluation of the therapeutic efficacy of HA sole therapy or        chemosensitizing therapy demonstrated that it was not toxic to        normal tissue and it did not enhance the toxicity profile of the        drug. In fact, mice receiving the therapy displayed a        significant weight gain over the 6-week treatment period and a        reduction in lymph node metastasis. The co-administration of HA        and 5-FU had a dramatic effect on the reduction of the primary        tumour volume; and    -   3). Mice who had HA incorporated into the treatment regimen did        not display the formation of any secondary tumour (FIG. 6).        Future Studies

Experiments are presently being conducted on the use of HA for in vivotreatment of breast cancer. These experiments are focusing on the effectof HA concentration and molecular weight and on the cytotoxicity ofadriamycin. It is the aim of these studies to also establishing drug andHA exposure time and regimens, as well as the mechanism of action of HA,i.e.: receptor mediated transport and/or effect on cell membrane.Further data on the role of HA in chemosensitizing drug-resistant cancercells will also be collected.

Section 1:

All studies will be conducted on breast cancer cell lines that expressdiffering levels of HA receptors, CD 44 and RHAMM. Cell lines to betested, MDA-MB 435, MDAMB 231, MDA-MB 468, ZRL-751 and several MDR-1expressing breast cancer cell lines.

Investigation of the effect of HA/adriamycin exposure times andconcentration on drug-resistant and drug-sensitive breast cancer cells.Four MDR-1 positive and 4 MDR-1 negative cell lines will be exposed toadriamycin at 1, 2.5, 5, 10, 20, 40, 60, 80 and 100 nM, the followingvariables will be tested:

-   1). 1 h drug±100 nM HA exposure followed by 3 days of drug-free    growth;-   2). Constant drug exposure±100 nM HA for 3 days 30 min 100 nM HA    exposure, followed by drug for 1 h, cells grown drug-free for 3    days; and-   3). 24 h 100 nM HA exposure, followed by drug for 1 h, cells grown    drug-free for 3 days.

These experiments will establish; optimal HA exposure times andregimens, magnitude of increased adriamycin cytotoxicity when combinedwith HA and whether HA can overcome efflux pump resistance in breastcancer cells.

To date the IC₅₀ of adriamycin has been determined as 90 nM. Using 90 nMof adriamycin the HA (700 kD) concentration will be varied to 1, 3, 10,30, 100, 300 nM, 11M, 3 μM, 10 μM, 30 μM and 100 μM. The incubationvariables to be tested are:

-   1). 30 min HA exposure followed by 1 h drug exposure cells grown    drug-free for 3 days;-   2). 24 HA exposure followed by 1 h drug exposure cells grown    drug-free for 3 days; and-   3). HA±drug exposure for 1 hr, cells grown drug-free for 3 days.

Any detached cells will be tested for cell viability since it has beensuggested that HA can play a pivotal role in cancer cell detachment andmigration. If detached cells are viable the HA receptor status will bedetermined using FACS surface epitope identification. Similarexperiments will be performed with short HA oligiosaccharides, ie: 4sacc, 6 sacc, 12 sacc, 5600 Da, 50,000 Da, 100,000 Da, 250,000 Da.

These experiments will demonstrate the optimal HA:drug ratio in vitro,optimal HA exposure time and regimen, effect of HA molecular weight onadriamycin cytotoxicity.

After determining the optimal HA concentration, the IC₅₀ of adriamycinwill be used in a series of time i course experiments to observe anyeffect of HA on adriamycin metabolism.

The [¹⁴C] adriamycin will be exposed to the cells for 30 min, 1 h, 2 h,4 h, 8 h, 16 h and 24 h. The experimental conditions will be:

-   1). Exposure of cells to HA for 30 min followed by drug; and-   2). Exposure of cells to HA for 24 followed by drug Co-exposure of    HA/adriamycin.

Cells will be removed, hypotonically lysed and centrifuged at 113,000gav for 1 hr. The membrane pellet and supernatant will be counted andanalyzed for metabolites using HPLC.

Cells will also be grown on coverslips, where they will be exposed toadriamycin±HA (exposures regimen as above) and a confocal photographytime course will be used to track the cytosolic uptake and movement ofthe drug.

Identification of HA Receptors on MDR-1 positive and negative breastcancer cell lines, FACS quantitation of the CD44s, CD44v6, CD44v10 andRHAMM receptors will be conducted. Quantitation of the HA/receptorbinding and saturation kinetics using FITC/HA and FACS analysis willalso be done.

By exposing the cells to:

-   1). HA for 30 min followed by drug;-   2). HA for 24 h followed by drug; and-   3). HA/adriamycin    We will be able to determine any of these block CD44s and RHAMM    receptors. The receptor status of any viable cells will be    quantitated using surface epitope FACS analysis. If blocking of the    HA receptors decreases the normally observed synergism between    adriamycin and HA, the membrane bound and cytosolic adriamycin will    be quantited t HA receptor blocking.

HA degradation by cell lines using [³H]HA and gel filtrationchromatography±receptor blocking will be studied.

HA of molecular weight, 4 sacc, 6 sacc, 12 sacc, 5600 Da, 50,000 Da,100,000 Da, 250,000 Da, 750,000 Da and 1,500,000 Da will be incubatedwith breast cancer cell lines at pre-determined “observed-effect”concentrations and the following will be parameters investigated:Extracellular and intracellular calcium flux (cellular probe assays).Regulation of cytoskeletal components (micro-array of cytoskeletalgenes), effect on volume of cells (Coulter size Analysis) and mobilityof cancer cells (Boyden Chamber matrigel assays) will also be conducted.

The effect of HA on the cell cycle will be undertaken by incubating HAof molecular weight, 4 sacc, 6 sacc, 12 sacc, 5600 Da, 50,000 Da,100,000 Da, 250,000 Da, 750,000 Da and 1,500,000 Da with breast cancercell lines at pre-determined “observed-effect” concentrations. Cellswill be labeled with potassium iodide and subjected to FACS analysis.The number of cells in each stage of the cell cycle will be determined.

Comparisons of the in vitro efficacy of the liposomal Doxorubicin andHA/Doxorubicin preparations will be conducted using the optimalHA/Doxorubicin preparation and the dosage range used by the LiposomeCompany in the pre-clinical testing of the liposomal doxorubicin.

Section 2:

Before progression of the HA/adriamycin anti-cancer therapy into Phase Ihuman breast cancer trials it is necessary to conduct preliminarytoxicity experiments. The experiments will focus on:

-   1). Effect of hyaluronan on adriamycin uptake in mouse body organs    and fluids;-   2). Establish a preliminary dose range for adriamycin Determine if    HA targets adriamycin to human breast tumour xenografts in nude    mice;-   3). Compare the commercial liposomal Doxorubicin to HA/doxorubicin    uptake in mice; and-   4). Comparison of short-term efficacy of liposomal doxorubicin and    HA/doxorubicin.

From Inaba et al, (1988) the dose of adriamycin in nude mice was 4 mg/kgwhich is a human equivalent dose of 60 mg/m². Nude mice bearing humantumours will be injected with adriamycin±HA. Using adraimycinconcentrations of 4 mg/kg±12.5 mg/kg HA. The experimental protocol willinclude the following treatment groups:

-   1). 4 mg/kg adriamycin;-   2). 4 mg/kg adriamycin+12.5 mg/kg HA; and-   3). 4 mg/kg liposomal doxorubicin.

Using adriamycin±HA will be quantitatively injected into the tail veinof the mouse.

At the time intervals of 2, 15, 30, 60 min and 1.5, 2, 4, 8, 24 and 48 h(4 animals/time point) the mice will be killed by a 0.1 ml IP injectionof Nembutal. All body organs, skeletal muscle, lymph nodes, bone marrow,urine and blood will be removed and the adriamycin content determinedusing HPLC and fluorescence.

Human breast tumours will be generated in nude mice (WEHI CBA strain).The mice will be injected with:

-   1). Mouse LD₅₀ is 10 mg/kg;-   2). 4 mg/kg adriamycin;-   3). 4 mg/kg adriamycin+12.5 mg/kg HA;-   3). 8 mg/kg adriamycin;-   4). 8 mg/kg adriamycin+12.5 mg/kg HA;-   5). 4 mg/kg liposomal doxorubicin;-   6). Saline; and-   7). 12.5 mg/kg HA.

The above mentioned will be quantitatively injected into the tail veinof the mouse (8 animals/group) on Days 2, 4, 6 of a weekly cycle.

Tumour volume, body mass, food intake and functionality of the mice willbe monitored on a daily basis.

At the completion of the 8-week study the mice will be killed by a 0.1ml IP injection of Nembutal. All body organs, tumour, skeletal muscle,lymph nodes, bone marrow, urine and blood will be removed processed forpathological assessment.

Section 3:

To answer some basic questions about the effect of HA anti-cancertherapy on colon cancer cells the following experiments should beconducted.

Investigation of the effect of HA/5-FU exposure times and concentrationon drug-resistant and drug-sensitive colon cancer cells.

Three resistant and 3 sensitive cell lines will be exposed to 5-FU at 1,2.5, 5, 10, 20, 40, 60, 80 and 100 nM, the following variables will betested:

-   1). 1 h drug±100 nM HA exposure followed by 3 days of drug-free    growth;-   2). Constant drug exposure±100 nM HA for 3 days;-   3). 30 min 100 nM HA exposure, followed by drug for 1 h, cells grown    drug-free for 3 days; and-   4). 24 h 100 nM HA exposure, followed by drug for 1 h, cells grown    drug-free for 3 days.

Using the IC₅₀ of 5-FU as determined as above, HA (700 kD) concentrationwill be varied to 1, 3, 10, 30, 100, 300 nM, 1 μM, 3 μM, 10 μM, 30 μMand 100 μM. The incubation variables to be tested:

-   1). 30 min HA exposure followed by 1 h drug exposure cells grown    drug-free for 3 days;-   2). 24 HA exposure followed by 1 h drug exposure cells grown    drug-free for 3 days; and-   3). HA±drug exposure for 1 hr, cells grown drug-free for 3 days.

Any detached cells will be tested for cell viability since it has beensuggested that HA can play a pivotal role in cancer cell detachment andmigration. If detached cells are viable the HA receptor status will bedetermined using FACS surface epitope identification.

Similar experiments will be performed with short HA oligiosaccharides,ie: 4 sacc, 6 sacc, 12 sacc, 5600 Da, 50,000 Da, 100,000 Da, 250,000 Da.

After determining the optimal HA concentration, the IC₅₀ of 5-FU will beused in a series of time course experiments to observe any effect of HAon adriamycin metabolism.

The [³H] 5-FU will be exposed to the cells for 30 min, 1 h, 2 h, 4 h, 8h, 16 h and 24 h. The experimental conditions will be:

-   1). Exposure of cells to HA for 30 min followed by drug; and-   20. Exposure of cells to HA for 24 followed by drug Co-exposure of    HA/5-FU.

Cells will be removed, hypotonically lysed and centrifuged at 113,000gav for 1 hr. The membrane pellet and supernatant will be counted andanalyzed for metabolites using HPLC.

Cells will also be grown on coverslips, where they will be exposed to5-FU+HA (exposures regimen as above) and a confocal photography timecourse will be used to track the cytosolic uptake and movement of thedrug.

Identification of HA Receptors on resistant and sensitive colon cancercell lines, FACS quantitation of the CD44s, CD44v6, CD44v10 and RHAMMreceptors, Quantitation of HA/receptor binding and saturation kineticsusing FITC/HA and FACS analysis will be done.

Blocking of CD44s and RHAMM receptors with inhibitory antibodies, apply5-FU±HA following the protocols of:

-   1). Exposure of cells to HA for 30 min followed by drug; and-   2). Exposure of cells to HA for 24 followed by drug co-exposure of    HA/5-FU.

Cells will be counted. The receptor status of any viable cells will bequantitated using surface epitope FACS analysis.

If blocking of the HA receptors decreases the normally observedsynergism between 5-FU and HA, the membrane bound and cytosolic 5-FUwill be quantited±HA receptor blocking.

HA degradation by cell lines using [³H]HA and gel filtrationchromatography±receptor blocking will be studied.

Effect of HA on the plasma membrane

Hyaluronan of molecular weight, 4 sacc, 6 sacc, 12 sacc, 5600 Da, 50,000Da, 100,000 Da, 250,000 Da, 750,000 Da and 1,500,000 Da will beincubated with breast cancer cell lines at pre-determined“observed-effect” concentrations and the following will be parametersinvestigated:

-   1). Extracellular and intracellular calcium flux (cellular probe    assays);-   2). Regulation of cytoskeletal components (micro-array of    cytoskeletal genes);-   3). Effect on volume of cells (Coulter size Analysis);-   4). Mobility of cancer cells (Boyden Chamber matrigel assays);-   5). Quantitation of HA receptors (FACS); and-   6). Membrane potential (method to be determined). An investigation    of the role of HA neo-adjuvant therapy on the inhibition of organ    metastasis will be undertaken.

In comparison to other treatment groups, mice receiving the HA therapyhave demonstrated that:

-   1). Reduced lymph node metastasis as compared to other treatment    groups;-   2). Inhibition of new tumour formation;-   3). Increased weight gain; and-   4). Enhanced well-being.

These results highlight the possible role of HA anti-cancer therapy asan efficient means of reducing the spread of cancer. Through theobligatory choice of a pre-clinical model there is a restriction,whereby the spread of the secondary cancer normally occurs in thesurrounding lymph nodes. It would be advantageous to use a model wherewe can examine the spread of the cancer to every organ and the bone. Byusing a model known as the BAG vector metastasis model we would be ableto monitor the spread of cancer to every organ and the bone.

In brief, the BAG vector consists of a neomycin-resistant LacZ gene thatcan be stably transfected into human breast cancer cells. Afterintracardiac injections into the nude mice, followed by a 6-weektreatment program it is possible to PCR detect the LacZ gene in anymetastasizing cells/organs. Faxitron scanning with detection of bonelesions would detect any bone metastasis.

The below treatments will be administered on Day 1, Day 2 of a weeklycycle, for 6 weeks. The treatment groups (5 animals per group) willconsist of:

-   1. Saline-   2. 30 mg/kg 5-FU Day 1, Day 2;-   3. 12.5 mg/kg HA Day 1, Day 2;-   4. 30 mg/kg 5-FU+12.5 mg/kg HA (co-administered on Day 1, Day 2);-   5. 12.5 mg/kg HA on Day 1, 30 mg/kg 5-FU on Day 2, 12.5 mg/kg HA on    Day 3, 30 mg/kg 5-FU on Day 4;-   6. 12.5 mg/kg HA on Day 1, 3;-   7. 30 mg/kg 5-FU on Day 2, 4;-   8. 15 mg/kg MTX Day 1, Day 2;-   9. 15 mg/kg MTX+12.5 mg/kg HA (co-administered on Day 1, Day 2);-   10. 12.5 mg/kg HA on Day 1, 15 mg/kg MTX on Day 2, 12.5 mg/kg HA on    Day 3, 15 mg/kg MTX on Day 4;-   11. 15 mg/kg MTX on Day 2, Day 4;-   12. 15 mg/kg MTX, 30 mg/kg 5-FU, 30 mg/kg cyclophosamide on Day 1,    Day 2; and-   13. 15 mg/kg MTX, 30 mg/kg 5-FU, 30 mg/kg cyclophosamide+12.5 mg/kg    HA on Day 1, Day 2;-   12.5 mg/kg HA on Day 1, (15 mg/kg MTX, 30 mg/kg 5-FU, 30 mg/kg    cyclophosamide) on Day 2, 12.5 mg/kg HA on Day 3, (15 mg/kg MTX, 30    mg/kg 5-FU, 30 mg/kg cyclophosamide) on Day 4.    Neo-Adjuvant Therapy:

Immediately before intracardiac injection administer the following:

-   1). 12.5 mg/kg HA;-   2). 15 mg/kg MTX;-   3). 15 mg/kg MTX, 12.5 mg/kg HA;-   4). 30 mg/kg 5-FU;-   5). 30 mg/kg 5-FU, 12.5 mg/kg HA;-   6). 15 mg/kg MTX, 30 mg/kg 5-FU, 30 mg/kg cyclophosamide; and-   7). 15 mg/kg MTX, 30 mg/kg 5-FU, 30 mg/kg cyclophosamide+12.5 mg/kg    HA.

Mouse mass and well being will be monitored daily for 6 weeks. Oncompletion of the treatment cycle, each mouse will be scanned for bonelesions. After scanning each organ and body fluid will be removed. Asufficient cross section of the organ will be kept for possible futurepathological analysis, while the remaining tissue will be homogenizedand subjected to competitive PCR for the detection of the LacZ gene.

Any organs which exhibit metastasis will be histologically processed andthe pattern of colonization of the cancer cells will be noted usinggalactosidase staining of the Lac Z gene.

Example 5 In vitro Comparison of Camptosar® (CPT-11) and Camptosar®(CPT-11) Combined with Hyaluronic Acid

Materials and Methods

Human Colon Carcinoma Cell Lines HT-29, HCT-116, SK-CO-1, SW620, SW1222were obtained from the Peter MacCallum, Cancer Institute, Melbourne.Cells were routinely grown and subcultured as a monolayer in 75 cm²culture flasks in RPMI 1640 media containing 10% fetal calf serum and 10μg/ml antibacterial/antimycotic stock in a humidified atmosphere of 5%CO₂.

Human colon carcinoma cell lines 1215 and LIM2099 were kindly donated byDr R Whitehead, Ludwig Institute, Melbourne. Cells were routinelycultured as monolayer in 75 cm² culture flasks in RPMI1640 mediasupplemented with 5% fetal calf serum, 10 μg/ml bovine insulin, 1 mMhydrocortisone and antibacterial/antimycotic stock

Preparation of Colon Cancer Growth Medium Containing 100 nM Hyaluronan(Modal MW 850,000 Da)

To prepare the 100 nM HA growth medium, a quantity of desiccated HA (MW850 kD) was used to the above-mentioned growth medium. The HA wasdissolved at 4° C. for a minimum of 8 h before sterilization byfiltration through a 0.22 μm filter.

Preparation of Camptosar for Addition to Colon Cancer Growth Medium+100nM Hyaluronan (modal MW 850,000 Da)

A stock solution of 20 mg/ml of Camptosar® was purchased from Pharmaciaand Upjohn, and was brought to a working concentration of 2 mg/ml withgrowth media as specified above. The various concentrations ofCamptosar® were achieved by diluting in the appropriate amount of growthmedia

Drug Cytotoxicity Assay

The HCT-116, HT-29, SK-CO-1, LIM1215, LIM2099, SW620 and SW1222 celllines were routinely grown to 80% confluency. The cells were removedfrom the culture flask and counted using the haematocytometer. The cellsHT-29, HCT-116, SK-CO-1, SW620 and SW1222 were resuspended to 15,000cells/ml of cell-specific media. The LIM1215 and LIM2099 wereresuspended to 30,000 cells/ml of cell-specific media. The cells wereplated into 48 well culture plates (1 cm² surface area) by adding 1 mlof cell suspension per well. The cells were allowed to attach overnightprior to exposure to the test media. The cells were continuously exposedto the following concentrations of test media: 0 μg/ml, 0.25 μg/ml, 0.5μg/ml, 1 μg/ml, 5 μg/ml, 25 μg/ml and 50 μg/ml Camptosar®±100 nMhyaluronan (Modal Mw 850,000). It should be noted that the terms“Camptosar®”, “irinotecan” and “CPT-11” are all terms for the samecompound and are used interchangeably throughout the specification andclaims of this application. The cells were continuously incubated withthe test media for 48 hours. On the day of analysis, the cells werewashed with Hanks Balanced Salt Solution. Subsequently, the cells wereremoved by trypsinization with 0.25% trypsin/EDTA. An aliquot of thetrypsinized cell suspension was counted by the Coulter Counter.

Method of Data Analysis

The raw duplicate or triplicate counts per well were obtained from theZ₂ coulter counter. The counts will be averaged and will be expressed aspercentage of no drug control.

Mean cells/ml of each replica was calculated using the following formula(A)

$\frac{\left( {{{Raw}\mspace{14mu}{counts}\mspace{14mu}{cells}\text{/}{ml}\mspace{14mu} 1} + {{raw}\mspace{14mu}{counts}\mspace{14mu}{cells}\text{/}{ml}}} \right)}{2}$Mean cells/ml of 4 wells (B) per conditions was calculated using thefollowing formula (A):

$\frac{\left( {{A1},{A2},{A3},{A4}} \right)}{{no}\mspace{14mu}{of}\mspace{14mu}{replicate}}$

Let A1, A2, A3 and A4 represents mean cells/ml of each replica

-   -   % of no drug control was calculated with the following formula:

$\frac{(B)}{{Average}\mspace{14mu}{of}\mspace{14mu}{control}\mspace{14mu}{{well}/{plate}}} \times 100$Coefficient of variance was calculated with the following formula:

$\frac{{Standard}\mspace{14mu}{deviation}\mspace{14mu}{of}\mspace{14mu}{mean}\mspace{14mu}{of}\mspace{14mu}{all}\mspace{14mu}{four}\mspace{14mu}\%\mspace{14mu}{of}\mspace{14mu}{no}\mspace{14mu}{drug}\mspace{14mu}{control}}{{mean}\mspace{14mu}{of}\mspace{14mu}{all}\mspace{14mu}{four}\mspace{14mu}\%\mspace{14mu}{of}\mspace{14mu}{no}\mspace{14mu}{drug}\mspace{14mu}{control}} \times 100$

If the coefficient of variance was more than 15%, outliers were deletedfrom the set of data.

The percentage of no drug control from two or more sets of experimentson the same cell line was pooled to obtained the average, standarddeviation and standard error of the mean. The graph was plotted as thevalues of the pooled percentage of no drug control with thecorresponding concentrations of Camptosar® with or without. HA±SEM.

Comparison of Camptosar® treatment group with HA combined with Camptosarwas achieved by statistical analysis using parametric t-test analysis.On failing of normal distribution, implementation of non-parametricanalysis will be carried out using the Mann-Whitney Rank Sum test. Thedate is presented in Table 8.

TABLE 8 IN VITRO STUDIES Cancer IC₅₀ of Camptosar ® IC₅₀ of HyCAMP ™Cell Line Type (μM) (μM) LIM 1215 Colon 16 1 SW 620 10 0.4 LIM 2099 3131 SK-CO-1 5 5 SW1222 32 32 HT-29 16 12 HCT-116 1.5 1.5

Example 6 In Vivo Toxicology Data

Materials and Methods

Animal Model

Male Out-bred male F1 CBAXC57 mice were purchased from The AnimalCentral Services Division (Monash University, CLAYTON, Australia) andrandomly divided into experimental groups (n=5/group). Treatmentcommenced when mice attained the desired starting weight of 27.1±2.1 g(1 SD). Any animals with a body weight outside these parameters wereexcluded from data analysis.

Preparation of Drugs and Control Vehicles for Intravenous Administration

The anti-cancer drug, Camptosar® (CPT-11) was kindly donated fromPharmacia Corporation R & D Global Distribution Center (Kalamazoo,Mich., USA). A 20 mg/mL stock of CPT-11 was prepared and stored at 4° C.until use (diluted to 10 mg/mL in 0.9% (w/v) pyrogen-free injectiongrade NaCl and used to prepare Camptosar® and HyCAMP™ injections.Desiccated hyaluronan (HA), was purchased from Pearce Pharmaceuticals(Victoria, Australia). A single batch of 10 mg/mL solution was preparedby Biological Therapies (Braeside, Victoria, Australia), packaged intosingle use 100 mL sterile glass vials and underwent standard chemicaland microbiology testing.

Individual injections were prepared according to individual animalmasses. The dosage of Camptosar® in both formulations was 25 mg/kg, 50mg/kg, 100 mg/kg, 150 mg/kg and 200 mg/kg. HyCAMP™ (hyaluronan mixedwith Camptosar®) was prepared immediately before injection by mixingcalculated volumes of 10 mg/mL hyaluronan (Biological therapies Batch10806) with a calculated volume of 20 mg/mL Camptosar® to achieve thedesired Camptosar® and hyaluronan dosage.

Frequency of Drug and Control Vehicle Administration

Five treatment groups received daily injections until death of thefollowing drug combinations and stated dosages.

Camptosar® only: 25 mg/kg, 50 mg/kg, 100 mg/kg, 150 mg/kg or 200 mg/kgor HyCAMP™: (Hyaluronan combined with Camptosar® to deliver an HA doseof 13.3 mg/kg and a Camptosar® dose of 25 mg/kg, 50 mg/kg, 100 mg/kg,150 mg/kg or 200 mg/kg)

All injections were administered as a single bolus intravenous injectionvia the lateral tail vein.

The following data was recorded: Injection Mass; Food Intake; AnimalObservations; Clinical Observations; and Animal Autopsy.

Definition of Experimental End Point

Unless otherwise stated in experimental notes the end point of thisstudy was when: >10% loss of body mass within 24 hours; animal energylevel <1+; or any animals found dead.

Processing of Tissues at Experimental Endpoint

At experimental endpoint mice were humanely killed by intraperitonealinjection of Nembutal (60 mg/mL). Immediately after death, all internalorgans were subsequently removed, weighed and fixed in 10% formalin inphosphate buffered saline. After a period of 16-24 hours of fixation thegastrointestinal tract was sampled and processed for histologicalprocessing. In brief, fixed tissue was dehydrated stepwise to 100%ethanol prior to embedding in paraffin blocks from which 2-4 μm sectionswere cut onto glass microscope slides (Note: all histological processingwas performed in The Department of Anatomy, Monash University inaccordance with internal quality assurance programs). Mounted sectionswere then stained with haematoxylin nuclear stain and eosin cytoplasmicstain. Any remaining tissues were kept in the fixative in case they wererequired for further analysis.

Monitoring of Treatment Side-Effects

Gastro-Intestinal Tract Toxicity, Weight Loss: One of the Most CommonToxic Effects of Camptosar® is on the gastrointestinal tract. Animalswere monitored daily throughout the study for visual signs of GI-tracttoxicity such as diarrhoea and more severe toxicity manifestations suchas weight loss. For demonstration of any weight changes the animal bodyweight was normalised to the body weight at the time of treatmentcommencement and expressed as a percentage.

To monitor and score the severity of diarrhea each rat was individuallyassessed for acute onset diarrhea 30 minutes after the administration ofCamptosar®/HyCAMP™ and control vehicles. The following coding system wasused:

0: Normal stool, or absent

1: Slightly wet soft stool

2: Moderate wet and unformed stool with moderate perianal staining

3: Severe watery stool with severe perianal staining

Clinical Observations: Autonomic, Behavioural and Neurological Profile

Immediately after a single bolus administration of either Camptosar® orHyCAMP™ the acute clinical response to the injection was monitored andsubsequently repeated at 30 minutes post injection. An Autonomic,Behavioural and Neurological profile was observed and scored daily,prior to, immediately after and 30 minutes after injection. Whereclinical signs were scored on a scale of 0, 1, 2, & 3, prior toinjection a baseline value of 0 was set. Immediately after giveninjection the acute response was observed (B-0′) and thereafter at 30minutes (B-30′). Where scoring was recorded as present or absent, absentwas set 0 and present to 1. For statistical comparisons of recovery, the0′-30′ (the difference in observed side effects from the timeimmediately post injection to 30 minutes post injection) value was used,where a positive value indicated reaction worsening with time whereas anegative value indicated a better reaction to injection with time.

Analysis of Data

Comparison of treatment and control group data was achieved bystatistical analysis using parametric t-test analysis. On failing ofnormal distribution, implementation of non-parametric analysis wascarried out using:

-   i) Mann-Whitney Rank Sum-   ii) One-way Anova

Data was represented graphically by column, scatter and column meanplots. A line graph was used where data was represented as a function oftime.

To investigate possible treatment induced organ atrophy or enlargement,the organs were removed and weighed during the post mortem.

The source data including the mouse and tumour masses were the massesrecorded on the Animal Autopsy Sheet. Any animals found dead were notincluded in the data analysis.

The mass of each organ was calculated as a % of the net body weight atautopsy and compared to the organ masses of the saline only controlgroup.

The source data was the measurements recorded on the Animal ObservationSheet. Any animals found dead were not included in the data analysis.

The source data was the measurements recorded on the Food Intake Sheet.Any animals found dead were not included in the data analysis.

The average amount of food consumed per day per mouse as a percentage ofthe mean net body mass was calculated using the following formula:

$\frac{{\left( {{food}\mspace{14mu}{{{eaten}(g)}/{number}}\mspace{14mu}{of}\mspace{14mu}{days}} \right)/{number}}\mspace{14mu}{of}\mspace{14mu}{rats}\mspace{14mu}{in}\mspace{14mu}{box}}{{net}\mspace{14mu}{body}\mspace{14mu}{mass}} \times 100$

Male F1 CBAXC57 mice were randomly distributed into five treatmentgroups (n=5). Treatment groups received either Camptosar® or HyCAMP™ atthe following doses: 25 mg/kg Camptosar®±13.3 mg/kg hyaluronan; 50 mg/kgCamptosar®±13.3 mg/kg hyaluronan; 100 mg/kg Camptosar®±13.3 mg/kghyaluronan; 150 mg/kg Camptosar®±13.3 mg/kg hyaluronan; or 200 mg/kgCamptosar®±13.3 mg/kg hyaluronan.

The treatment regime comprised of daily injections for 14 days or untilanimal morbidity. At the experimental end-point all organs were weighedand the GI-tract was processed for histopathological assessment oftoxicity.

Results

This study demonstrated that animals receiving 25 mg/kg Camptosar®(CPT-11) or HyCAMP™ survived for 14 days and were able to receive anaccumulative dose of 350 mg/kg drug without experiencing severe adverseeffects. Animals receiving 25 mg/kg Camptosar® lost 18% body (p>0.001)when compared to the HyCAMP™ treatment group which received anequivalent dose of irinotecan hydrochloride. Animals receiving thisdosage of irinotecan hydrochloride did not exhibit any immediateneurological toxicity, early or late on-set diarrhea.

Further, animals receiving 50 mg/kg Camptosar® did not survive past 12days where the LD₅₀ was 475 mg/kg over 9-10 days. At 14 days aftercommencement of treatment, 60% of animals receiving 50 mg/kg HyCAMP™survived and the LD₅₀ was never reached. Animals receiving HyCAMP™ wereable to receive an accumulative dose of 700 mg/kg drug withoutexperiencing severe adverse effects. No significant difference inend-point weight loss was observed between the different treatmentgroups where weight loss was 15.2 to 20.7% of body weight. Animalsreceiving this dosage of irinotecan hydrochloride did not exhibit anyimmediate neurological toxicity, early or late on-set diarrhea.

Moreover, animals receiving 100 mg/kg Camptosar® did not survive past 7days where the LD₅₀ was 550 mg/kg over 5-6 days. At 14 days aftercommencement of treatment, 12.5% of animals receiving 100 mg/kg HyCAMP™survived and the LD₅₀ was 1150 mg/kg over 11-12 days. Animals receivingCamptosar® exhibited neurological effects 30 seconds after injection andit took 5 h to fully recuperate, while animals receiving HyCAMp™ alsodemonstrated neurological side-effects 30 seconds after injection buthad fully recuperated 30 min after injection. No significant differencein end-point weight loss was observed between the different treatmentgroups where weight loss was 26.8 to 31.6% of body weight. Animalsreceiving Camptosar® experienced Grade 2-3 diarrhea while animalsreceiving HyCAMP™ experienced Grade 1-2 diarrhea.

Animals receiving 150 mg/kg Camptosar® and HyCAMP™ exhibitedneurological effects 30 seconds after injection and the Camptosar® groupdid not recuperate. The HyCAMP™ treatment group recuperated within 90minutes but after a single dose were found dead after 48 h. Animalsreceiving 200 mg/kg Camptosar® and HyCAMP™ exhibited neurologicaleffects 30 seconds after injection where the Camptosar® group did notrecuperate. Lastly, animals treated with 50-100 mg/kg of Camptosar®demonstrated a significant increase in the mass of the stomach, lungs,spleen and brain when compared to the HyCAMP™ treatment group

Animals could receive bolus injections of 25-100 mg/kg Camptosar® wherethe LD₅₀ was demonstrated to be approximately 475 to 550 mg/kg. Animalscould receive bolus injections of 25-100 mg/kg HyCAMp™ where the LD₅₀was demonstrated to be approximately 1100-1200 mg/kg. The lethal dose ofCamptosar® was found to be >100 mg/kg, whereas the lethal dose ofHyCAMP™ was found to be ≧200 mg/kg.

The grade of diarrhea and weight loss was reduced in animals receivingHyCAMP™ versus animals receiving Camptosar®, suggesting that theco-administration of hyaluronan alters the gastrointestinal toxicityoften associated with irinotecan hydrochloride.

Through the reduction in weight loss and diarrhea, animals receivingHyCAMP™ demonstrated increased survival over the Camptosar™ treatmentgroups.

This study has clearly demonstrated that the co-administration ofhyaluronan with irinotecan hydrochloride attenuates the toxicity ofirinotecan hydrochloride so enabling the administration of higher doses.

Example 7 In Vivo Efficacy Data

The following experiment was performed to determine whether theco-administration of hyaluronan with irinotecan hydrochloride (HyCAMP™)increases the efficacy of irinotecan hydrochloride in the treatment ofcolon cancer, and/or reduce treatment toxicity.

Material and Methods

Human LIM 1215 colon cancer xenografts were inoculated into the mammaryfat pad of athymic Balb/c/WEHI nude mice. Mice were randomly distributedinto eight treatment groups (8 mice per group).

Treatment groups received 50 mg/kg irinotecan±13.3 mg/kg HA; 50 mg/kgirinotecan±26.6 mg/kg HA; or 50 mg/kg irinotecan±150 mg/kg HA.

Control groups received either saline or 13.3, 26.6 or 150 mg/kg HA. Thetreatment regime comprised of injections on Day 1 of a 7-day cycle forduration of fourteen weeks. Primary tumor volume, animal body mass,energy levels and food consumption were monitored three times weekly.

Colon Carcinoma Cell Line

The human colon carcinoma cell line LIM1215 colon carcinoma cell linewas kindly donated by Dr R Whitehead, Ludwig Institute, Melbourne. Thecell line was routinely cultured as monolayer in 75 cm culture flasks inRPMI1640 media supplemented with 5% fetal calf serum, 10 μg/ml bovineinsulin, 1 mM hydrocortisone and antibacterial/antimycotic stock. Forgeneration of the primary tumor and injection into mice, cells weregrown to 80% confluency, trypsinised in 0.05% trypsin/0.01% EDTAsolution, washed twice by centrifugation in a Beckman TJ-6 benchcentrifuge (Beckman, Melbourne, Australia) at 400 gav for 10 min,counted using a Model-ZM Coulter counter (Coulter Electronics, England)and resuspended in RPMI1640 media at 2×108 cell/ml.

Mouse Tumor Model

Athymic CBAIWEHI nude female mice (Walter and Eliza Hall ResearchInstitute, Melbourne, Australia), 6 to 8 weeks old, were maintainedunder specific pathogen-free conditions, with sterilized food and wateravailable ad libitum. Each mouse received one injection containing 1×10⁷cells in 50-100 μl. The cells were injected with a 26-gauge needle intothe mammary fat pad directly under the first nipple. Tumor measurementswere made weekly by measuring three perpendicular diameters (d₁d₂d₃)using digital calipers. Tumor volume was estimated using the formula:(⅙)π(d₁d₂d₃)

Treatment with irinotecan±HA was commenced after approximately 4-8 weeksof tumor growth when the mean tumor volume measured <100 mm³ (SEM, 10mm³) and the tumor volume expressed as a percentage of body weight was<0.5%. Any animals with a tumor volume expressed as a percentage of bodyweight outside 0.25±0.10 (mean±1SD) were excluded from data analysis.

Tumor Volume

The source data was the measurements recorded on the Animal ObservationSheet. The tumour mass data required for the Hydration Value was sourcedfrom the Animal Autopsy Sheet. The following analysis was performed onthe raw data:

The starting tumour volume was defined as the tumour volume (mm3) on theday treatment commenced (i.e., Day 1).

The starting tumour volume as a percentage of net body weight wascalculated using the following formula:

$\frac{{starting}\mspace{14mu}{tumour}\mspace{14mu}{{volume}\left( {cm}^{3} \right)} \times 100}{{net}\mspace{14mu}{body}\mspace{14mu}{{weight}(g)}\mspace{14mu}{on}\mspace{14mu}{Day}\mspace{14mu} 1}$where net body weight was estimated by subtracting a calculated tumourweight (1 g×tumour volume (cm³)) from total mouse body weight.

Tumour volume at experimental end-point was defined as the tumour volume(mm³) on the day of death. For animals which were found dead the tumourvolume measured at the last observation was used.

Percentage change in tumour volume at experimental end-point wascalculated using the following formula:

$\frac{\begin{matrix}{{{end}\text{-}{point}\mspace{14mu}{tumour}\mspace{14mu}{{volume}\left( {mm}^{3} \right)}} -} \\{{starting}\mspace{14mu}{tumour}\mspace{14mu}{{volume}\left( {mm}^{3} \right)} \times 100}\end{matrix}}{{starting}\mspace{14mu}{tumour}\mspace{14mu}{{volume}\left( {mm}^{3} \right)}}$

The therapeutic effectiveness of anti-cancer treatments are oftencompared to untreated tumours (saline control group). This wascalculated using the following formula:

$\frac{\begin{matrix}{\%\mspace{14mu}{change}\mspace{14mu}{in}\mspace{14mu}{tumour}\mspace{14mu}{volume}\mspace{14mu}{at}\mspace{14mu}{experimental}} \\{\;{{end}\text{-}{point}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu}{Treatment}\mspace{14mu}{group} \times 100}}\end{matrix}}{\begin{matrix}{{\%\mspace{14mu}{change}\mspace{14mu}{in}\mspace{14mu}{tumour}\mspace{14mu}{volume}\mspace{14mu}{at}}\mspace{11mu}} \\{{experimental}\mspace{14mu}{end}\text{-}{point}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu}{Control}\mspace{14mu}{group}}\end{matrix}}$

The mean tumour volume was calculated for each week of the treatmentperiod and plotted±SEM as a function of time using the followingformula:

$\frac{{sum}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu}{tumour}\mspace{14mu}{{volumes}\left( {mm}^{3} \right)}\mspace{14mu}{of}\mspace{14mu}{each}\mspace{14mu}{mouse}}{{number}\mspace{14mu}{of}\mspace{14mu}{mice}}$

A well vascularized, viable tumour contains more mass and has a lowerwater content than a necrotic, poorly vascularized tumour. Thisrelationship was examined by calculating the Hydration Value whichindicates the mass (mg) of each mm³ of tumour using the followingformula:

$\frac{{end}\text{-}{point}\mspace{14mu}{tumour}\mspace{14mu}{{volume}\left( {mm}^{3} \right)}}{{autopsy}\mspace{14mu}{tumour}\mspace{14mu}{{mass}({mg})}}$

Following the completion of the 14-week study, mice from each treatmentgroup were classified into one of four categories based on the extent oftheir tumour progression. The categories and criteria for each were asfollows (Maucher & von Angerer, 1994):

i) Complete remission: Tumour not palpable ii) Partial remission: Tumourvolume <50% of initial (equates to values <−50% change in tumour volumeat experimental end-point) iii) Static Tumours: Tumour volume 50-150% ofinitial (equates to values between −50 and 150% change in tumour volumeat experimental end-point) iv) Progressing Tumours: Tumour volume >150%of initial (equates to values >150% change in tumour volume atexperimental end-point)Preparation of irinotecan and Hyaluronan Drug Combinations

Desiccated hyaluronan Modal M_(r) 800 kD-850 kD was dissolved in sterilewater to a final concentration of 10 mg/mL, filter sterilized through a0.22 μm filter, and stored at 4° C. until used. A stock solution of 20mg/ml of Irinotecan was purchased from Pharmacia and Upjohn and wasdiluted to 4 mg/mL in intravenous grade sodium chloride then used toprepare irinotecan and HyCAMP injections. The dosage of HA administeredremained at 13.3 mg/kg throughout the study. The dosages ofirinotecan/HyCAMP administered were 50 mg/kg.

Mice were randomly distributed into each of eight treatment groups (8mice per group). Individual mice were placed in an injection box, andtreatment administration was via the tail vein using a 26-gauge needle.To ensure the accuracy of each administered dosage, syringes wereweighed before and after injection using an analytical balance.

TABLE 9 Treatment Administration Protocol for 14-week Study TreatmentGroup Animal Dosage Injection Day Saline 0.9% Injection Grade Day 1 of 7Day Cycle* HA 13.3 mg/kg HA Day 1 of 7 Day Cycle* HA 26.6 mg/kg HA Day 1of 7 Day Cycle* HA  150 mg/kg HA Day 1 of 7 Day Cycle* Irinotecan   50mg/kg irinotecan Day 1 of 7 Day Cycle* HyCAMP   50 mg/kg irinotecan +13.3 mg/kg Day 1 of 7 Day Cycle* HA *: for fourteen weeks HyCAMP   50mg/kg irinotecan + 13.3 mg/kg Day 1 of 7 Day Cycle* HA *: for fourteenweeks HyCAMP   50 mg/kg irinotecan + 26.6 mg/kg Day 1 of 7 Day Cycle* HA*: for fourteen weeks HyCAMP   50 mg/kg irinotecan + 13.3 mg/kg Day 1 of7 Day Cycle* HA *: for fourteen weeks

The experimental end-point for each animal occurred either when theanimal had to be euthanized due to a high degree of disease progressionor when the 14-week study had been completed. The animals were monitoredthree times weekly and the following criteria were established todetermine whether an animal had reached the experimental end point:tumour mass is greater than 10% of the animals total body mass; theanimal is metabolically stressed (i.e. losing weight); or the animal isimmobilized.

Following the experimental end-point being reached, each animal waskilled by receiving a lethal dose of 100 μl Nembutal (60 mg/ml) byintraperitoneal injection and cervical dislocation. Animals were weighedand tumor volumes measured.

Immediately after killing the mouse the tumor, liver, heart, spleen,bladder, left and right kidneys, uterus, lungs, stomach, intestines,brain and lymph nodes were excised and weighed and placed in 10%formalin buffered solution. The tissue was fixed for 16-24 h beforehistological processing. Fixed tissue was dehydrated stepwise to 100%ethanol and embedded in paraffin blocks from which 2-4 μm sections wereplaced on glass microscope slides. Staining the tissue sections with ahaematoxylin nuclear stain and eosin cytoplasmic stain highlighted anypathological features that could indicate treatment toxicity.

One of the most common toxic effects of irinotecan is on thegastrointestinal tract (MIMS, 2000). Animals were monitored three timesweekly for GI tract upset such as diarrhoea and more severe toxicitymanifestations such as weight loss. Weight loss was monitored bycalculating net body weight as estimated by subtracting tumour mass,which was calculated as 1 g×tumour volume (cm³) as cited in Shibamoto etal, 1996. For demonstration of any weight changes the animal body weightwas normalized to the body weight at the time of treatment commencementas

$\frac{\begin{matrix}{{{Body}\mspace{14mu}{{mass}\left( {{ex}\mspace{14mu}{tumour}} \right)}} - {{body}\mspace{14mu}{mass}\mspace{14mu}{at}}} \\{{commencement}\mspace{14mu}{of}\mspace{14mu}{{treatment}\left( {{ex}\mspace{14mu}{tumour}} \right)}}\end{matrix}}{{Body}\mspace{14mu}{mass}\mspace{14mu}{at}\mspace{14mu}{commencement}\mspace{14mu}{of}\mspace{14mu}{{treatment}\left( {{ex}\mspace{14mu}{tumour}} \right)}} \times 100$

Due to the severe side effects associated with irinotecanadministration, animal energy levels were monitored three times weeklyto give an indirect assessment of animal health. Each animal was scoredon an arbitrary four-point scale, ranging from 0 (minimally energetic)to 4+ (maximally energetic). In judging energy levels, such factors asmobility, interest in surroundings, response to stimuli and generalactivity were considered. In plotting energy level data, animals thathad reached the experimental end-point were scored as zero to minimisebiased data representation due to decreased animal survival.

Immediately after a single bolus administration of either irinotecan orHyCAMP the acute clinical response to the injection was monitored andsubsequently repeated at 30 minutes post injection. A full autonomicprofile of each mouse will be recorded. Where clinical signs were scoredon a scale of 0, 1, 2, & 3, prior to injection a baseline value of 0 wasset. Immediately after given injection the acute response was observed(B-0′) and thereafter at 30 minutes (B-30′). Where scoring was recordedas present or absent, absent was set 0 and present to 1. For statisticalcomparisons of recovery, the 0′-30′ (the difference in observed sideeffects from the time immediately post injection to 30 minutes postinjection) value was used, where a positive value indicated reactionworsening with time whereas a negative value indicated a better reactionto injection with time.

To ensure that treatments did not induce organ atrophy or enlargement,the organs were removed and weighed during the post mortem blood. Themass of each organ was calculated as a % of the overall net body weight,and compared to the organ masses of the saline only group.

The overall patient survival time was calculated as the time (days orweeks) that the animal lived after the commencement of treatment whichwas designated day 1.

Results

The efficacy of irinotecan as an anti-neoplastic agent was increasedwhen co-administered with HA. More specifically, mice receiving 50 mg/kgHYCAMP™ demonstrated significantly greater tumor regression than micereceiving the equivalent irinotecan dosage, including complete tumorregression in 17% of mice. No significant differences in tumor responsewere noted in HyCAMP™ formulations containing 13.3, 26.6 or 150 mg/kgHA.

Throughout the study in the mice receiving irinotecan alone, tumorvolume regressed to a maximum of 50% of starting volume. This wasobserved by weeks 6-8 and thereafter became non-responsive to furthercycles of irinotecan chemotherapy. In contrast, HyCAMP™ therapycontinued to regress tumor volume to approximately 90% of originalstarting volume.

As evidenced by the hydration value of a tumor, HyCAMP™ therapy tumorsconttumors statistically significant higher mass of necrotic tissue whencompared with mice receiving irinotecan treatment.

Weight gain in treatment groups was retarded when compared with controlgroups. The difference in the degree of observed weight loss in theirinotecan and HyCAMP™ treatment groups was comparable.

Mice receiving HYCAMP™ therapy resulted in 100% population survivalwhereas treatment with irinotecan resulted in approximately 57% of thetreatment group surviving to the end of the 14-week study.

Lastly, the increase in targeting of irinotecan to the pathologicalsite, when combined with hyaluronan, was correlated to the confirmedpresence of high levels of C44 expression on the cell surface of LIM1215by FACS analysis.

The results of this study are presented in Table 10. These findingsdemonstrate the potential of HA in the targeting and delivery ofirinotecan to colon cancer tumors, thereby increasing therapeuticefficacy and increasing population survival.

TABLE 10 HyCAMP ™ Species/ No./ Route of Dose Administration Strain SexAdmin. (mg/kg) schedule Results/Observations Mouse 8F IV bolus 13.3 HADay 1 of All animals treated with HA had progressive disease and no CBAnude 8F 26.6 HA 14 × q7D treatment toxicity was observed 8F  150 HA 8F50 Camptosar ® ± 13.3HA The efficacy of Camptosar ® was increased whenco- 8F 50 Camptosar ® ± 26.6HA administered with HA. More specifically,mice receiving 8F 50 Camptosar ® ± 150HA 50 mg/kg HyCAMP ™ demonstratedsignificantly greater tumor regression than mice receiving theequivalent Camptosar ® dosage; 100% of HyCAMP ™ animals had a completeremission or partial response versus a 28% of the animals treated withCamptosar ®. At experimental end-point population survival in HyCAMPtreated mice was 100% whereas mice receiving Camptosar ® therapy wasonly 57%.

Example 8 Effect of Hyaluronan as a Cytotoxic Compound for theInhibition of Cancer

Effect of HA on Cell Proliferation

To determine if hyaluronan could act as an anti-proliferative or evencytotoxic compound in vitro the following experiments were performed.

CD44-positive and CD44-negative breast cancer cells were incubated with0.7 to 8 ng/cell of HA having the following molecular weight: 396, 792,1584, 2376, 30 kDa, 110 kDa, 190 kDa, 220 kDa, 260 kDa, 824 kDa, 1600kDa and 5000 kDa for 48 h. This experiment demonstrated that at a MWless than 30 kDa, the HA was able to exert a cytotoxic effect at alltested concentrations (see FIG. 7).

Limits of HA in Breast Cancer Cell Lines

To determine the upper and lower concentration threshold of 750 kD HAthree breast cancer cell lines were incubated with 10⁻¹⁵ M to 10⁻⁶ M HA.Cells were grown in the presence of the HA for three days, then cellswere subjected to the cell adhesion assay procedure. HA exhibited aslight anti-proliferative effect on both the CD-44 positive MDA-MB 468and MDA-MB 435 breast cancer cell lines (see FIGS. 8A-B). At 1 pM to 1μM HA reduced proliferation up to 20% in the MDA-MB 468 cell line and upto 25% in the MDA-MB 435. Since HA production is an integral componentof mitosis the presence of large amounts of exogenous HA may result in anegative feedback which signals the cancer cells into senescence andtherefore would inhibit them from metastasizing to other organs.

Effect of HA on Breast Cancer Cell Morphology

To investigate if HA altered the morphology of human breast cancercells, human breast cancer cell line MDA-MB 468 was exposed to 750 kD HAfor 24 h and then photographed. At 10 ng/ml there was a reduction incell number, but no difference in morphology. At 100 ng/ml and 1 mg/mlthe cells appeared to be undergoing an osmotic response where the cellsappeared to “swell”. At 2 mg/ml and 5 mg/ml the cells became granularand appeared to be undergoing apoptosis once again ensuring that thecells would not metastasize to secondary organs.

Tumor Volume in Vivo

To determine the effect of HA on tumor volume in vivo, 12.5 mg/kg of HAwas administered on day 1 and 2 of a 7 day cycle for 6 cycles and 12.5mg/kg on day 1 and 3 of 7 day cycle for 6 cycles (FIG. 9A) or 12.5 mg/kgon day 1 and 8 of 28 day cycle for 6 cycles (FIG. 9B). HA routinelyresulted in a lower % T/C, where in 3/3 experiments the differencereached significance (p<0.001, Student t-test). This anti-proliferativeeffect could be due to the degradation of the HA into apoptotic-inducingfragments and/or the microembolisation effect, which could result intissue hypoxia and subsequent cell death.

HA Accumulation in Tumors

It has been well established that high molecular weight hyaluronaninhibits cell migration (see, for example, Dube et al., Andreutti etal., Ferns et al., and Tamoto et al.), therefore the accumulation ofhigh molecular weight HA within a tumor could inhibit tumor cellmigration to secondary organs, hence preventing metastasis. Todemonstrate that after a single bolus dose of intravenous HA there was aprolonged accumulation of high molecular weight, 15.9 mg/kg of [³H]HA(MW of 825 kD) was intravenously injected into female nude mice bearingMDA-MB 468 human breast cancer xenografts. Mice (n=5/time point) werekilled at 15 min, 30 min, 60 min, 2 h, 4 h, 8 h, 24 h, 48 h and 72 hafter intravenous administration. Chromatographical analysis of thetumor homogenate demonstrated that after one bolus injection of 825 kDa[³H]HA the high molecular weight rapidly aggregated within themicro-vasculature of the tumor resulting in a microembolic effect whichwas observed for up to 8 h. The microembolization of the HA did notprevent the internalization of the HA into the tumor cells asdemonstrated by the identification of cellular metabolic end-products of³H-acetate and water in the tumor homogenates. Macromolecular HA (ModalM_(r)˜825 kDa) was present for up to 24 h after intravenousadministration suggesting a slow rate of turnover (FIG. 10). It isimportant to consider that these data were obtained after a single bolusinjection. When applied to the clinical situation where anti-cancerdrugs are often administered over an extended infusion period it islikely that the HA microembolism would continue to form and maintain itsintra-tumoral presence for longer thereby potentially increasing the HAretention and concentration within the tumor. Therefore based on thesedata it is possible that in the clinical situation the intra-tumouralconcentration of HA may be high enough to result in an inhibition oftumor cell metastasis.

Example 9 Effect of Hyaluronan on the Proliferation of Human Breast andColon Cancer Cell Lines

The effect of HA on the proliferation of human breast and colon cancercell lines was determined according to the methods set forth in theTable 11.

TABLE 11 HA Receptor status (%) Effect of HA on cell proliferation*Incubation Cancer Cell (mean ± standard deviation) Conditions LinesCD44s^(a) CD44v6^(b) RHAMM^(b) 100 nM 500 nM 10 μM BREAST CANCER 3 daysconstant MDA MB 468 80 0 50  99 ± 6 (n = 20)  95 ± 3 (n = 8)  99 ± 6 (n= 20) exposure MDA MB 435 50 50 75  85 ± 17 (n = 16)  55 ± 6 (n = 8) 101± 1 (n = 8) MDA MB 231 50 80 75 106 ± 11 (n = 20) 100 ± 1 (n = 8) 101 ±5 (n = 8) ZR-75-1 0 0 38 103 ± 4 (n = 20) 102 ± 1 (n = 8) 100 ± 3 (n =8) 30 min HA followed MDA MB 468 80 0 50  97 ± 15 (n = 12) NOTDETERMINED by growth for 3 MDA MB 435 50 50 75  86 ± 6 (n = 12) days MDAMB 231 50 80 100  86 ± 3 (n = 8) 24 H HA followed MDA MB 468 80 0 50  84± 1 (n = 4) NOT DETERMINED by growth for 3 MDA MB 435 50 50 75 111 ± 6(n = 8) days COLON CANCER 3 days constant LIM 1215 100 ND ND  89 ± 5 (n= 8) NOT DETERMINED exposure SW620 4 ND ND  97 ± 1 (n = 8) LIM 2099 NDND ND 105 ± 2 (n = 16) SK-CO-1 ND ND ND  95 ± 3 (n = 8) SW1222 13 ND ND 99 ± 1 (n = 8) HT-29 46 ND ND  82 ± 14 (n = 8) HCT-116 74 ND ND  92 ± 0(n = 8) ^(a)As compared to normal epithelial cells using dot blotanalysis⁶⁶ ^(b)As determined by immunohistochemistry or FACS in theHyaluronan Laboratory *Number expressed as % of untreated control

Example 10 Summary of the Effect of 750 kD OR 825 kD HA on Breast andColon Cancer Xenografts, Metastasis, Body Mass and Survival in vivo

The following table sets forth the results of the administration of HAon breast and colon cancer xenographs, metastasis, body mass andsurvival in vivo.

TABLE 11 TV % change in TV % animals with % change in NBM SurvivalAdministration (Mean ± SEM) during treatment LN mets# during treatment(Mean + SEM) Test Compound Regimen Day 0 Endpoint % T/C (Mean ± SEM) N =6–8 (Mean ± SEM) (days) MDA-MB 468 Breast cancer xenografts in nude miceSaline Day 1 & 2  40 ± 5  241 ± 40 100  504 ± 96 87.5   0.09 ± 1.87  42± 0 of 6 × q7D 12.5 mg/kg of 750 kD Day 1 & 2  51 ± 6  163 ± 41 47  239± 78 0   2.59 ± 1.00  42 ± 0 HA of 6 × q7D 12.5 mg/kg of 750 kD Day 1 &3  29 ± 7  52 ± 23 13   66 ± 30* 0   0.91 ± 1.59  42 ± 0 HA of 6 × q7DSaline Day 1  32 ± 11  395 ± 60 100  1305 ± 258 12.5   19.3 ± 2.0  43 ±0 of 6 × q7D 13.3 mg/kg of 825 kd Day 1  53 ± 8  384 ± 85 45  588 ± 61*12.5   18.0 ± 2.0  43 ± 0 HA of 6 × q7D Saline Day 1 & 8  43 ± 6 1114 ±198 100  2777 ± 618 50 −3.02 ± 3.05 118 ± 8 of 6 × q28D 12.5/kg of 750kD HA Day 1 & 8  53 ± 7  795 ± 211 68  1875 ± 682 28.5 −6.26 ± 6.64 121± 10 of 6 × q28D □Saline Day 1 & 8 210 ± 18 1656 ± 292 100  547 ± 125100   4.39 ± 3.93 130 ± 14 of 6 × q28D 12.5/kg of 750 kD HA Day 1 & 8175 ± 24 1424 ± 329 143  780 ± 241 25   6.10 ± 3.29 150 ± 11 of 6 × q28DLIM 1215 Colon cancer xenografts in nude mice Saline Day 1  30 ± 2 1702± 151 100  5812 ± 725   13.3 ± 4  92 ± 4 of 7 × q13D 13.3 mg/kg of 825kD Day 1  36 ± 3 1635 ± 129 81  4706 ± 501   11.3 ± 3  93 ± 4 HA of 7 ×q13D Saline Day 1  30 ± 2  357 ± 61 100  1114 ± 206    7.2 ± 3  50 ± 0of 7 × q7D 13.3 mg/kg of 825 kD Day 1  36 ± 3  401 ± 42 97 11077 ± 133   5.2 ± 2  50 ± 0 HA of 7 × q7D 26.6 mg/kg of 825 kD Day 1  36 ± 3  260± 39 60  671 ± 132  −0.5 ± 2  50 ± 0 HA of 7 × q7D Abbreviations used intable: D = Days; q7D = 7 day cycle: q28D = 28 day cycle: #Lymph nodemetastasis as determined by CEA immunohistochemistry of paraffinsections Statistical significance using Student t-test (p = 0.001) % T/Ccalculated as % change in tumor volume over treatment period oftreatment group as % of tumor volume over treatment period of salinegroup

Example 11 Evaluation of HyDOX™ in the Treatment of Breast Cancer inBreast Cancer Xenographs

CD44-Positive Breast Cancer Xenografts

In comparison to DOX (doxorubicin) treatment groups, HyDOX™ (aformulation comprising HA and DOX) significantly reduced the tumourvolume of breast cancer when it was administered for 6 cycles consistingof Days 1 of a 7-day cycle at a dosage of 80 mg/m² (FIG. 11A).

To gauge the therapeutic effectiveness of DOX versus HyDOX™ tumorviability in animals treated with HyDOX was compared to animals treatedwith DOX (FIG. 11B).

CD44-Negative Breast Cancer Xenografts

Treatment groups successfully completed 5 weekly cycles over theduration of the 42-day study. Measurements of the % change in tumourvolume over the treatment period are shown in FIG. 12. Unlike previousstudies in CD44-positive tumours, HyDOX™ did not significantly increasethe therapeutic efficacy when compared to the DOX group.

Comparison of doxorubicin, HyDOX™ and Caelyx in CD44-Positive BreastCancer Xenografts

As the most commonly used form of doxorubicin is in a pegylatedliposomal preparation known as Caelyx, it was necessary to compare theefficacy of HyDOX™ versus the industry-preferred product. As seen inFIG. 13, HyDOX™ demonstrated a greater tumour response than theliposomal preparation.

Cardiotoxicity

In the HyDOX™ efficacy study there were indications of reduced cardiacdamage and due to the well-established fact that DOX causes chroniccardiac damage thereby restricting its clinical usefulness. A study wasspecifically designed to address the potential protective role of HyDOX™against cardiac damage.

Differentiated rat myocardiocytes were exposed to varying concentrations(ranging from highest therapeutic exposure of 1 μM to the averagecirculating dose of 270 nM, when assuming a 80 mg/m² injection). Cellswere subjected to the previously described cell adhesion cytotoxicityassay. HyDOX™ with a HA component of 10 μM or 11 μg/ml which is lowerthan the circulating levels of HA which follows an injection of 60 mg/m²of HYDOX™ protected the cardiomyocytes from the cytotoxicity of DOX(FIG. 14).

Example 12 Comparison of Doxorubicin, HyDOX™ In Vivo

In order to compare the effect of doxorubicin and HyDOX™ in vivo, sixtreatment groups each consisting of 8 hypertensive rats wereadministered the following treatment: 1) no treatment, 2) Hyaluronan(13.3 mg/kg, IV injection), 3) saline, 4) doxorubicin (1.5 mg/kg, IVinjection), or HyDOX (1.5 mg/kg doxorubicin; 13.3 mg/kg HA).

Animals were injected on a weekly basis for 12 weeks. One week afterfinal treatment the rats were humanely killed and the heart removed forassessment of cardiac damage. Assessment of cardiac damage was performedby to directly assess the degree of doxorubicin-generated vacuolation ofthe cardiac myocytes using electron microscopy. Sections of theintraventricular septum from rat hearts were processed for EM analysis.The degree of cardiomyopathy was scored by an adaptation of theBillingham method. Cumulative amount of doxorubicin and HyDOX™ over the12 week period=19.5 mg/kg. The results of this experiment indicate thatit is possible to administer 2-3 times the dose of HyDOX beforeobtaining the same degree of cardiomyocyte vacoulation (FIG. 15).

Example 13 Bone Marrow Toxicity

In order to determine if HyDOX™ was toxic to bone marrow, circulatingerythrocytes, platelets and white cell sub-populations were quantified.The results indicate that lower doses of HyDOX™ (FIGS. 16A and B)significantly increased the number of circulating polymorphic whitecells.

REFERENCES

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INCORPORATION BY REFERENCE

The contents of all references, patents, pending patent applications andpublished patents, cited throughout this application are herebyexpressly incorporated by reference.

EQUIVALENTS

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

1. A method of treating cancer comprising intravenously administering to a subject in need thereof a therapeutically effective amount of hyaluronan prior to the administration of at least one cancer chemotherapeutic agent, wherein the hyaluronan is intravenously administered from 24 hours to 30 minutes prior to the intravenous administration of the cancer chemotherapeutic agent and wherein the hyaluronan has a size expressed as a molecular weight of 750,000 to 1,500,000 Daltons.
 2. The method according to claim 1 wherein the hyaluronan has an intrinsic viscosity of 10.0 dl/gm to 14.5 dl/gm.
 3. The method according to claim 2 wherein the modal molecular weight of hyaluronan is 750,000 Daltons.
 4. The method according to claim 2 wherein the modal molecular weight of hyaluronan is 1,500,000 Daltons.
 5. The method according to claim 1 wherein the cancer is selected from the group consisting of breast, lung, prostate, kidney, neural, ovary, uterus, liver, pancreas, epithelial, gastric, intestinal, exocrine, endocrine, lymphatic, haematopoetic system or head and neck tissue.
 6. The method according to claim 1 wherein the subject is a mammal.
 7. The method according to claim 6 wherein the mammal is selected from the group consisting of bovine, canine, equine, feline, porcine and human.
 8. The method according to claim 1 in which the cancer chemotherapeutic agent is selected from the group consisting of carmustine (BCNU), cisplatin (Platinol), Cytarabine, doxorubicin (Adriamycin), 5-fluorouracil (5FU), methotrexate (mexate), irinotecan (CPT-11), etoposide, plicamycin (Mithracin) and taxanes.
 9. The method according to claim 8 wherein the cancer chemotherapeutic agent is 5-fluorouracil.
 10. The method according to claim 8 wherein the cancer chemotherapeutic agent is irinotecan.
 11. The method according to claim 8 wherein the cancer chemotherapeutic agent is doxorubicin.
 12. The method according to claim 1 wherein the hyaluronan is administered from 24 hours to 1 hour before the administration of the cancer chemotherapeutic agent.
 13. The method of claim 1 wherein the hyaluronan is administered from 12 hours to 30 minutes before the cancer chemotherapeutic agent.
 14. The method of claim 1 wherein the amount of hyaluronan in the composition is from 0.5 mg to 150 mg per kilogram body weight per day.
 15. The method of claim 1 wherein the amount of hyaluronan in the composition is from 5 mg to 40 mg per kilogram body weight per day.
 16. The method of claim 1, wherein the wherein the modal molecular weight of hyaluronan is about 850,000 Daltons. 